Washington, Nov 6 (AP) Republicans in Congress have spent most of the year acquiescing to US President Donald Trump's demands -- they've quickly confirmed his Cabinet nominees, passed his “big beautiful bill” of tax and spending cuts and kept his broad tariffs in place despite deep reservations.

But Trump is finding that Senate Republicans have a limit as he aggressively pushes them to scrap the filibuster, the longstanding Senate rule that requires 60 votes to pass most legislation.

The filibuster “makes the Senate the Senate", Majority Leader John Thune has said, arguing that the votes are not there to change the rules. He and other Republicans stress that the filibuster has benefited their side when Democrats have power.

Trump has long disagreed. At a breakfast with Senate Republicans on Wednesday morning, he renewed his calls to end the government shutdown by getting rid of the filibuster and lowering the threshold to 51 votes for legislation.

Democrats have been using the filibuster as leverage as they demand an extension of expiring healthcare subsidies as part of a bill to fund the government.

“It's time for Republicans to do what they have to do, and that's terminate the filibuster,” Trump, who made similar demands in his first term, said.

Returning to the Capitol immediately after the breakfast, Thune held firm.

“I know where the math is on this issue in the Senate and it's not happening,” he said.

The GOP pushback suggests Republicans who have been unfailingly loyal to the president are determined to protect the institution of the Senate beyond his time in office, mindful that no party stays in power forever.

But Trump has faced little resistance from Congress in the first year of his second term, and continues to push Republicans to act despite their unequivocal rejection of the idea.

Some Republicans may be concerned about the future, Trump said earlier this week, but “we're here right now".

Senate institutionalists stand strong ====================== Republicans were outspoken about the need to keep the filibuster four years ago, when Democrats had the majority and tried to remove it. In the end, Democrats didn't have the votes.

Republicans, now holding a 53-47 majority, appear even further away from having the votes to end the filibuster.

The No. 2 Republican in the Senate, Wyoming Senator John Barrasso, has said he wouldn't support any changes.

Kentucky Senator Mitch McConnell was the GOP leader in Trump's first term and resisted his calls to eliminate it then.

Alaska Senator Lisa Murkowski said that she attended the White House breakfast and Trump did not change her mind. The filibuster “makes us different from these guys at the other end of the hall", she said, referring to the House.

“The filibuster forces us to find common ground in the Senate,” Senator John Curtis said last week, when Trump first called for Republicans to eliminate it. He said he is a “firm no” if the issue were to come up.

North Carolina Senator Thom Tillis said he could say “with metaphysical certainty this Congress is not going to nuke the filibuster, period, full stop".

Even Speaker of the House Mike Johnson has backed Thune, saying on Sunday that Republicans traditionally resisted calling for an end to the filibuster because it protects them from “the worst impulses of the far-left Democrat Party".

Small but growing number back idea ====================== Still, a few Republican senators have said they agree with Trump.

“If we need to bust it, let's bust it,” Alabama Senator Tommy Tuberville, a close Trump ally, said after the breakfast with Trump.

“Let's knock it down to 51 and let the Senate know that the power needs to go to the president and let him get something done. If we don't, we're going to lose our country. It's over.” Wisconsin Senator Ron Johnson said Trump made “a very convincing case” to the senators and that he talked to the president afterward about how they could potentially get it done.

Johnson said Republicans can't just sit back and be “schmucks", letting Democrats do it first if they get power.

“If you'd asked me a couple of years ago if I would support this, I would have said no,” Johnson said.

Protecting minority powers ================= Trump has also urged Republicans to get rid of so-called “ blue slips", a process in the Senate Judiciary Committee that allows the minority party to sign off on lower court judges in their home states.

But Thune and Senate Judiciary Committee Chairman Chuck Grassley have said the blue slips will stay.

Thune said earlier this year that the process enabled him to work with former president Joe Biden's administration when there was a judicial vacancy in South Dakota and Democrats held the Senate majority.

“I don't sense any rush to change it,” Thune said.

Republicans were also cool to another proposal from Trump late last year, when he floated the idea of recess appointments.

A day before Thune was elected leader by the GOP conference, Trump posted on social media that the next leader “must agree” to allow him to make temporary appointments when the chamber is on recess, bypassing a confirmation vote.

The Senate has not allowed presidents to make so-called recess appointments since a 2014 Supreme Court ruling limited the president's power to do so. (AP) ARI