“I’m talking to my Senate colleagues: here are the witnesses you should call and here are the questions you should ask,” said Rep. Chris Stewart (R-Utah). “It’s going to cast us in a different very light. This is a chance to tell the other side of the story.”

President Donald Trump has joined in as well, tweeting on Thursday that he wants to call Schiff, Speaker Nancy Pelosi and the Bidens as witnesses in his impeachment trial.

But Senate Republicans are beginning to deliver a reality check to the president and House Republicans that there are limits to what they can do.

“You got two different bodies here,” Graham, a stalwart Trump ally, told reporters on Thursday. “Are we going to start calling House members over here when we don’t like what they say or do? I don’t think so.”

Senate GOP leaders have signaled they intend to defend Trump wholeheartedly, but they’re also loath to let the upper chamber descend into chaos or divide their caucus ahead of a tough 2020 cycle. And even if Senate Republicans wanted to embrace the hard-line posture of the House, the party’s narrow majority makes that all but impossible under Senate rules.

Calling controversial witnesses will require near lockstep party unity from 51 of the 53 Senate Republicans to make any procedural maneuvers, a tough task given the diverse views in the GOP, according to senators and aides.

Senate Majority Leader Mitch McConnell (R-Ky.) has privately urged senators to avoid divisive votes on impeachment motions, and other senators are eager to ensure that the GOP doesn’t lose votes — or control of a trial in their own chamber.

So as carefully as they can, given the political need to stay aligned with Trump, GOP senators are pouring cold water on the idea that they can or will produce a Christmas tree of TrumpWorld demands during a trial that will determine whether Trump’s presidency survives the winter.

“I don’t feel like we necessarily need all of them. … It becomes a big circus of people and they call John Bolton and we call Hunter Biden. OK. We can do that,” said Sen. James Lankford (R-Okla.). “Is it needed to be able to make a decision based on the evidence we’re looking at right now?”

“If you get into a long convoluted [process], this thing could drag on for a really long time,” said Senate Majority Whip John Thune (R-S.D.). “If both sides get into a bunch of motions about who we bring who [Democrats] bring and we’re having numerous votes on that? I think that’s something, I think, in the end neither side is probably going to be crazy about.”

To establish the ground rules of a Senate trial, McConnell and Senate Minority Leader Chuck Schumer (D-N.Y.) will try and hash out a deal over length and other broad parameters. But when talk turns to calling witnesses, those votes seem likely to be intensely divisive, both between Democrats and Republicans and perhaps among Republicans themselves.