I am inclined to fantasize two things. First I imagine that Trump will attempt to place himself above the law (not a fantasy). Second I dream that Democratic Senators, two independents, McCain, Flake and Corker will resist with all instruments provided by The Constitution.
They can replace McConnell with one of them (say Corker). They can nuke the rules of the Senate. They can make 100 new committees Trump Russia committees 1 through 100 each consisting of one Senator with full power of subpoena.
They can hold Trumpers who resist Subpoenae in contempt of the Senate. The whole Senate can find them in contempt and propose that the House impeach. The 51 can keep the Federal Government open with weekly continuing resolutions and shut it whenever the Trump administration resists.
I think the Senate can clearly hold people in contempt -- that is have the sergeant at arms lock them up in some office.
Crazy and not enought.
Now 67 Senators and 290 Representatives can pass laws over vetoes. They can include making 535 committees with the power of subpoena and the rule that unelected employees of the US government found to be in contempt of Congress are not allowed on US government property. They can (by law) grant themselves the power to search and seize all US government property (maybe excluding property of the judiciary and stuff in the White House). This would require no warrants as the property already belongs to the US Government and the law describes what that means.
The power of veto and pardon won't cancel this law.
Crazy sure but 2017 is crazy.