House Democrats, who have spent the last two years half-suggesting that President Trump is a 21st-century Manchurian candidate, have a chance to do some diplomacy now that they've won back the House: The party plans to anoint one of its most temperamentally bipartisan and substantively moderate members to head the Foreign Affairs Committee.

“We are not going into this to try and exacerbate our differences; we're trying to find common ground,” New York Rep. Eliot Engel, the incoming Democratic chairman of the Foreign Affairs Committee, told the Washington Examiner.

That makes Engel an interesting choice for a precarious moment for the West. China is challenging the United States for economic and perhaps military hegemony. Russian President Vladimir Putin is content, for the moment, to draw new maps of its preferred corner of Europe, at gunpoint.

“I think it's good to try to show as much of a united front as you can,” Engel said in a recent interview. “Having said that, I also believe very strongly in the constitutional checks and balances and I think that the executive branch is certainly a branch of government, but, so is the legislative branch, certainly, and we're not subservient.”

But the Democratic voters who propelled Engel and his colleagues to the majority want a fight, preferably a big one. President Trump has pledged “a warlike posture” if Democrats launch a barrage of investigations. The domestic disputes have grown so intense that “nearly three-in-four foreign policy opinion leaders rated political polarization as a critical threat to U.S. national security,” per a recent survey from the Chicago Council on Global Affairs and the Texas National Security Network.

So, the 116th Congress will get a rare opportunity to find out if a system of government designed to “break and control the violence of faction” can work as intended when it's most needed.

Secretary of State Mike Pompeo’s team is wary. “I think Mike is willing to work with the Democrats, but if they just want to subpoena and investigate and politicize the State Department, then it's going to make it very difficult to work with them,” a source close to the secretary told the Washington Examiner. “He'll comply with their oversight as long as it has a purpose and as long as it's geared toward what everyone wants, which is strengthening the mission of the department.”

Pompeo has traded barbs already with Democrats on both sides of the Capitol. He derided “a political soliloquy” from New Jersey Sen. Bob Menendez, the ranking member on the Foreign Relations Committee, after Trump’s summit with Putin in Helsinki. His first appearance as the nation’s top diplomat before the House Foreign Affairs Committee showed that Democrats haven’t forgotten the role he played interrogating former Secretary of State Hillary Clinton over the Benghazi terrorist attack. Rep. Gregory Meeks, D-N.Y., in an apparent effort to give him a taste of his own medicine, suggested that Pompeo "does not care about diplomatic security."

You can hear the simmering tension even in some pledges to avoid needless fireworks. “They’re the ones that conducted investigations and abused subpoena power,” Meeks told the Washington Examiner. “We’re not going to do that. We’re not going to be the Republicans. We want to do what’s best for this country ... There’s a difference between investigations and oversight. Oversight is our responsibility.”

Engel’s temperament might contain the blasts. “I expect us to be forceful,” Pennsylvania Rep. Brendan Boyle, another another Democratic member of the committee told the Washington Examiner. “I expect us to work with the administration where we can, and I also think that we will — and Eliot sets the best tone for this — I think we will put the best interests of the country first.”

That leaves room for a wide range of disagreements with the Trump foreign policy agenda — “if you can even call it that,” Rep. Gerry Connolly told the Washington Examiner. “It’s all about American retreat.”

The Virginia Democrat, one of the leading progressives on the committee, sees weakness in almost every major theater of Trumpian foreign policy. He faults the president for his unwillingness to blame Russia unequivocally for its 2016 election interference, and for scrapping multiple pacts negotiated under former President Obama. The 2015 Iran nuclear deal is perhaps the most notable of these agreements, but liberal lawmakers haven’t forgotten the Paris climate accords. Many even regret the loss of the Trans-Pacific Partnership, a trade agreement with 11 Pacific Rim countries that Connolly believes would have helped restrain the “hungry wolf” that is China.

“It’s just a complete pattern of making America retreat,” Connolly said. “When you really examine it, the damage he's done is almost incalculable [and] it is breathtakingly broad. It may be irreversible. he may have engineered the permanent reduction in U.S. prestige and influence across the globe.”

Here's where the Democrats' united front begins to crack. Connolly regards the Iran nuclear deal as a diplomatic treasure of the Obama era, but Engel does not. He voted against the agreement in 2015 because “it did not prevent Iran from having a nuclear weapon” despite “being sold” otherwise. Engel opposed Trump’s decision to exit the deal, believing that the president should should have honored the commitments that Obama made, but he shares Pompeo’s assessment of the main threat to the region.

“Iran is the biggest destabilizer in the Middle East," Engel told the Washington Examiner.

And he agrees with the Trump team’s long-term plan for how to mitigate that threat: “I think that there is an opportunity here for there to be cooperation between some of the Sunni Arab states and Israel, because their leaders have to realize that Israel is not their enemy anymore — if it ever was — but that Iran is really the one that they need to guard against."

That includes Saudi Arabia, chief among the Sunni Arab states, despite the latest crisis over the murder of Washington Post columnist Jamal Khashoggi, a crime the CIA has concluded was ordered by Crown Prince Mohammed bin Salman. A bipartisan group of senators, led by Menendez and South Carolina Republican Lindsey Graham, have introduced a “comprehensive” rebuke of MbS, as he's known. The legislation calls for suspension of weapons sales to the Arab monarchy, an investigation of potential war crimes in Yemen — where a Saudi-led coalition is fighting a rebel force backed by Iran — and a report on human rights in Saudi Arabia.

Such ideas will find a warm welcome among House Democrats. “We have to hold everybody accountable in the region,” Meeks told the Washington Examiner. "We’ve got to make sure that in these kinds of wars that we're on the right side and where we do have allies that our allies are doing the right thing.”

Engel is likely to keep any punishment of Saudi Arabia within limits, even though he agrees Khashoggi's killing is “horrific” and is also “very angry” about Saudi Arabia’s bombing of Yemen. “If we're going to contain Iran, we're going to need Saudi Arabia's help, so we're sort of walking that fine line,” he told the Washington Examiner. “We've got to take some time to show our annoyance, [but] I don't think you slam the door,” he said.

Engel might feel pressure to indulge some of the investigations favored by the angriest portions of the Democratic base, if only to give him the political space to compromise on Iran and other issues.

Proponents of Obama’s Iran policy are taking a charitable view of Engel’s erstwhile heresy on the nuclear deal.

“The executive has ultimate say over the agreements and deals and pacts that the United States of America abides by, and so, even if Engel were in a different place substantively, there's only so much that one chamber of Congress can do,” Ned Price, a former CIA officer who served as spokesman for the White House National Security Council under Obama, told the Washington Examiner. “What that chamber is able to do, however, is to force the administration to answer the questions that they have so far skirted.”

House Democrats' role on Iran policy, he added will be to keep Team Trump from doing “anything dangerous and drastic" that could lead to war. "One of the guiding principles when it comes to Iran, for this administration, will need to be 'do no harm,’ " Price said. "And I think the Democrats in the House will be in a good position to do everything they can to ensure that the administration does no additional harm, in the hopes that this can somehow muddle through.”

If Iran debates scramble the typical political alliances, Connolly’s broader denunciation of Trump’s record also hints at areas of bipartisan cooperation. The White House National Security Strategy declares that “China and Russia challenge American power, influence, and interests, attempting to erode American security and prosperity.”

Democrats agree — but they worry the administration's actions don't reflect its words on that score, while the president's personal diplomacy softens the rhetorical blows delivered by his national security team.

“There are various places where the administration has adopted a sweep-it-under-the-rug strategy, hoping these tough questions don’t come,” Price said. “The administration has been able to stonewall and put on a happy face in a lot of these really profound national security challenges.”

Engel’s cohort of Democrats plan to press Pompeo about high-profile negotiations, such as the North Korea talks and various encounters with Putin. “I want to hear what exactly happened at the Helsinki summit,” Boyle said, referring to the one-on-one meeting that culminated in Trump blaming the United States for tension with Russia. “I would never in a million years imagine a President Reagan or a President Clinton or any previous president behaving in the disgraceful way that Donald Trump did, and I think it's something that we still have to explore."

The Pennsylvania Democrat also expects a hearing to take place on the administration's view of North Korea denuclearization talks, “where it seems to be looking the other way on an awful lot.”

Pompeo has refused to provide many details about those private diplomatic meetings. He touts the administration’s record of imposing sanctions on North Korea and Russia, in addition to providing weaponry that Obama declined to provide to Ukraine in their ongoing fight to roll back Russia’s annexation of Crimea and destabilization of eastern Ukraine.

“That’s where this administration is so disjointed,” Boyle said. “At one moment, Trump will say things and act like he just couldn't care less, frankly, about Ukraine or defending our Western allies. And then, the very next day, the administration will approve things that are supportive.”

Trump’s personal consistency, or lack thereof, in upholding his administration’s policies is something of a theme for his liberal critics.

“President Trump is happy to have this talking point that North Korea is no longer a threat,” Price said while touting the theory of “maximum pressure” on North Korea. “I think maximum pressure has to be the name of the game unless and until we see steps that are in the direction of complete verifiable, irreversible denuclearization and steps that are more than a handshake with President Trump.”

Connolly has a similar perspective on Trump’s approach to China, where he pulled out of TPP and then started a trade war with the Communist power.

“He's been so erratic, on so much, that I don't think China's all that afraid of him,” the Virginia Democrat told the Washington Examiner.

National security experts of all stripes agree that China has sheltered dictator Kim Jong-un’s regime from the full blast of economic sanctions. Here, Democratic prescriptions could dovetail naturally with the more hawkish elements of the administration. Rep. Brad Sherman, D-Calif., called for sanctions on the entire Chinese banking industry, as a punishment for their aid to North Korea, during a Foreign Affairs Committee hearing last year. More recently, he reminded his Democratic colleagues not to forget their historic frustration with China’s economic chicanery.

“We're now told that this is Trump's trade war,” Sherman said in July. “No, China declared trade war on the United States, 18 years ago.”

Connolly doesn’t expect to force Trump back into TPP, any more than the Obama diaspora thinks they can push the president back into the Iran deal. He wants a wide-ranging economic outreach to key nations in the region. But the threat posed by China — which is effectively buying strategically located ports around the world, while laying claim to vast and critical shipping lanes in the South China Sea — requires a deepening of military partnerships as well.

“We can beef up joint exercises with our allies in the region — Japan, South Korea, and, for that matter, Indonesia — to send a message that we are going to help beef up the military capabilities of countries that feel threatened by China's expansion in the South China Sea,” Connolly said.

He also suggested offering U.S. support to modernize the Philippines’ armed forces, in part to diminish the risk of China trying to win a quick conflict with the former U.S. colony.

“I think you want to create a situation that persuades the Chinese that that would be not only inflammatory, it would be profoundly risky behavior,” Connolly also said, "with consequences that they don’t really want.”

Pompeo might bristle at Democratic attacks, particularly Price’s suggestion that he won’t “look under the hood or to press the North Koreans too much further, because they'll be willing to accept the political boon” that Trump has enjoyed from the apparent progress in the talks.

But his team believes there's more common ground, even on the thorny issues, than many assume.

“I think there's actually a lot of agreement across the political spectrum on some of the things that the secretary wants to do with China and with Russia,” the source close to Pompeo told the Washington Examiner. “While they may disagree with the president, I think they'll find places with the secretary and the State Department that they'll be able to shape policy on what are our common enemies.”