The media have been laser-focused on President Trump's battles with Senate Republicans and his intelligence agency chiefs because when it comes to politics, there's nothing they love more than civil war.

But the greater threat to the president comes from the other party.

When Democrats won the House, there was plenty of prognostication about how they were going to use their newfound power to investigate the hell out of the administration. That faded for a while because by the time Nancy Pelosi got the gavel, the government was shut down.

But now that Washington is open for business — for the time being — the investigative machinery is starting to clank.

Congress, of course, has an obligation to oversee what the executive branch is doing. But there's a pretty clear line between that mission and burying the White House in a blizzard of subpoenas, hearings and demands for information.

The right is poised to accuse Pelosi's party of doing just that. It's the mirror image of the left accusing the GOP of obsessively investigating Benghazi, Fast and Furious and other problems in the Obama administration.

As someone who's covered dozens of such hearings, I can attest that oversight, with some exceptions, tends to be far more aggressive when the other party holds the White House.

The fencing has already begun, with The Washington Post reporting that "several Cabinet secretaries have already declined to testify before committees on contentious topics such as the impact of the shutdown and the administration's abandoned policy of separating migrant families."

Homeland Security chief Kirstjen Nielsen, for instance, blew off a committee request to testify about border security. The panel's chairman, Bennie Thompson, sent her a blistering letter and told the paper, "If she says she's not coming, we'll subpoena her to the committee. We need to hear from her." Nielsen offered alternative dates — during a week when Congress is out on recess.

Treasury chief Steve Mnuchin and HHS Secretary Alex Azar also ducked House invitations, offering to send other officials instead.

Here's the most interesting thing in the piece: Trump has told Pelosi, according to sources, that "if House Democrats begin investigating his administration, he will not negotiate with her on other issues."

At the same time, the Post says, Trump told the House speaker in a phone call that she is "great" and "terrific" and promised to work on infrastructure and prescription drug pricing. No wonder her nickname is just "Nancy."

Some clashes are inevitable in divided government. I covered fights between the Reagan administration and a Democratic House that escalated to contempt-of-Congress charges, though in the end they were settled.

But given the anti-Trump zeal among the Democrats, many of whose voters are ready to support impeachment, it's understandable why the president is girding for battle.

House investigations can be a powerful tool for a party that, until January, controlled nothing in Washington. But there's a danger for the Democrats if they're seen as resorting to harassment and intimidation.