A Major Challenge for Trump’s Agenda: A Mercurial Coach Calling the Plays

The president-elect has admonished Republicans to stay united around his ambitious domestic policy plans. But his track record with Congress is one of abrupt turnabouts and last-minute blowups.

House Republicans are decamping to Mar-a-Lago this weekend to huddle with President-elect Donald J. Trump and plot their strategy as they toil to unite around his behemoth of a legislative agenda.

But before they can do so, they need Mr. Trump to weigh in on an issue they have been agonizing over for weeks: how to structure and sequence his long list of priorities so it can make it through Congress.

They have been anxiously waiting for Mr. Trump to definitively declare his preference so they can set to work producing either one big bill or two more modest ones.

So far, he has mostly equivocated and sent mixed signals.

“Whatever it is — doesn’t matter,” Mr. Trump told reporters at the Capitol on Wednesday before meeting with Senate Republicans. “We’re going to get the result and we’re going to make America great again.”

It was a familiar reprise for Republican leaders who were around during Mr. Trump’s first term to experience how his changing moods, shifting priorities and flashes of rage could sap their leverage and derail even their best-laid plans. And it underscored a steep challenge they face as they try to put together consequential legislation aimed at cutting taxes, slashing spending and cracking down on immigration that he has demanded.

During his first term, Mr. Trump functioned less as a coach calling plays and more as a cantankerous owner demanding that his team throw out the entire playbook in the fourth quarter. In 2018, he threatened to veto a spending bill passed by a Republican-controlled Congress, only to relent. Months later, he threatened to veto an immigration bill backed by the speaker at the time, Paul D. Ryan, only to have his aides walk the comments back. In 2020, he said he would veto a $900 billion Covid relief and government funding bill, but signed it days later.