(CNN) During a campaign rally a little less than a year before he entered the White House, Donald Trump boasted that his supporters' loyalty was such that he "could stand in the middle of 5th Avenue and shoot somebody" with political impunity.

The rhetorical flourish struck a nerve, in part because it spoke to a fundamental truth about his campaign. Trump backers were all-in and there seemed to be nothing, no ugly revelation or gaffe, damaging enough to loosen the grip.

But after nearly two months in office, Trump is running up against more suspicious constituencies. Institutions he promised to conquer have shown themselves to be less inclined to forgive his missteps and foreign governments, including close allies like the UK, are making their concerns known. White House aides were forced to deliver what amounted to an apology Friday morning to their British counterparts -- then watch as Trump seemed to withdraw it during a press conference hours later.

Republican colleagues, with their own interests at stake, have become increasingly frustrated by "the daily tweets." And Democrats, emboldened by the administration's recent setbacks, are falling over themselves to point out where Trump has diverged from core campaign promises.

Congress and 'wire tapping'

Questions surrounding his baseless March 4 accusation that President Barack Obama "wire tapped" Trump Tower before the election might have dissipated or given way to another controversy in the furor of a campaign season. But Trump is president now, and while his base still loves him, his claims have put congressional Republicans and top national security staff in a bind.

Terrible! Just found out that Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism! — Donald J. Trump (@realDonaldTrump) March 4, 2017

Next Monday, the first House Intelligence Committee hearing on Russia's alleged interference in the 2016 election will put the spotlight on FBI Director James Comey, who will likely be asked about the claim. The chairman of that committee, California Republican Devin Nunes, a White House ally, told reporters on Wednesday that he has not seen any evidence to back the accusations.

"I don't believe Trump Tower was tapped," he said, as a bipartisan group of senators stepped up their criticism of the FBI, which has so far refused to answer questions, at least publicly, about potential surveillance of Trump and his campaign. Republican Sen. Lindsey Graham has threatened to subpoena information if Comey doesn't volunteer it.

JUST WATCHED Spicer: Trump stands by wiretapping claim Replay More Videos ... MUST WATCH Spicer: Trump stands by wiretapping claim 01:22

The wiretap episode represents the latest in a series of controversies created by Trump's rogue tweeting -- by his own words -- and stoked by the White House's attempts to deflect or deny the President had meant what he said. White House press secretary Sean Spicer has provided a range of explanations.

On Monday, he sought to play interpreter, telling reporters , "The President used the word wiretaps in quotes to mean, broadly, surveillance and other activities."

Trump echoed those remarks during a Wednesday night interview on Fox News , then promised again that the administration "will be submitting things" to Congress soon and promised, "you're going to find some very interesting items coming to the forefront over the next two weeks."

But on Thursday, Senate Intelligence Committee Chairman Richard Burr and ranking-member Mark Warner issued a broad statement saying that "based on the information available to us, we see no indications that Trump Tower was the subject of surveillance" -- not simply wiretapping -- "by any element of the United States government either before or after Election Day 2016."

In response to a question from CNN earlier in the day, House Speaker Paul Ryan conceded the same.

"The intelligence committees, in their continuing, widening, ongoing investigations of all things Russia, got to the bottom -- at least so far with respect to our intelligence community -- that no such wiretap existed," Ryan said.

Still, the White House pushed. Spicer during his Thursday briefing parroted an allegation made by a Fox News analyst claiming Obama had outsourced surveillance of Trump to British intelligence. UK officials, including the typically mum GCHQ, the equivalent of the American NSA, immediately dismissed the claim as "nonsense."

By Friday morning, senior administration officials told CNN that Spicer and national security adviser H.R. McMaster had, in separate conversations, offered what amounted to an apology to the British. But during a joint press conference with German Chancellor Angela Merkel in the afternoon, Trump refused to make a similar concession, instead telling a reporter, "You shouldn't be talking to me, you should be talking to Fox."

Republicans vs. Republicans vs. Trump (and his promises)

Don't worry, getting rid of state lines, which will promote competition, will be in phase 2 & 3 of healthcare rollout. @foxandfriends — Donald J. Trump (@realDonaldTrump) March 7, 2017

Trump during the campaign and just before his inauguration made a series of bold promises about his plans for the future of health care. In tweets and remarks about Obamacare, he pledged a complete overhaul and comprehensive replacement.

"We're going to have insurance for everybody," he told The Washington Post in January, days before taking office.

Trump had been consistent on that point. In September 2015, as his young primary campaign surged, he was asked on CBS' " 60 Minutes " about health care strategy.

"Obamacare's going to be repealed and replaced," Trump said, calling the law a "disaster."

Pressed to explain what he would replace it with, the candidate was characteristically bold.

"I am going to take care of everybody," he said. "I don't care if it costs me votes or not. Everybody's going to be taken care of much better than they're taken care of now."

In the run-up to his campaign and through the primary debates, Trump also distinguished himself from Republican opponents with a vocal defense of programs like Medicare, which he vowed not to cut.

I was the first & only potential GOP candidate to state there will be no cuts to Social Security, Medicare & Medicaid. Huckabee copied me. — Donald J. Trump (@realDonaldTrump) May 7, 2015

"I was the first & only potential GOP candidate to state there will be no cuts to Social Security, Medicare & Medicaid," he tweeted on May 7, 2015, a little more than a month before he entered the race.

That was then. Now Trump is in Washington, trying to negotiate a bill with ideologically splintered Capitol Hill Republicans. Medicaid in particular has become a point of contention in the talks, with conservative members calling for a swift end to the Obamacare expansion, while at least four moderate GOP senators -- enough to sink the bill if they all voted against it -- have lodged concerns about future cuts.

Sen. Tom Cotton, an Arkansas Republican, has casually dismissed Trump and House leaders' argument that an ugly CBO projection would be remedied with subsequent legislation.

"There is no three-step plan," Cotton told radio host Hugh Hewitt. "That is just political talk. It's just politicians engaging in spin."

JUST WATCHED GOP showdown over Obamacare repeal Replay More Videos ... MUST WATCH GOP showdown over Obamacare repeal 02:42

In this fight, Trump looks less the part of a typically compromised politician, hemmed in by campaign promises he is struggling to keep after being elected. And while he has, to date, maintained his support for the legislation drawn up by Ryan, Trump risks paying a real political price if the final product is so obviously different from what he sold the public for more than a year.

The ghost of Trump comments past haunts travel ban

This week, courts in Hawaii and Maryland blocked the implementation of the White House's second effort at a travel ban for six majority-Muslim nations, in both cases effectively dismissing administration efforts to clear legal hurdles by citing Trump's past stated desire to close the door on Muslim immigrants.

JUST WATCHED Trump responds to Hawaii travel ban ruling Replay More Videos ... MUST WATCH Trump responds to Hawaii travel ban ruling 03:37

A "watered down version of the first one," as Trump put it in Nashville on Wednesday night, the second order would halt immigration from six Muslim-majority countries for at least 90 days and reinstate a temporary ban on all refugees. It does not, like the initial order, prioritize any religious group for refugee admission.

Justice Department lawyers zeroed in on the question of intent and argued that Trump's past remarks should not be held against him, saying in their Hawaii brief that it was not the role of the courts to go poking underneath "the veiled psyche of government officers."

But US District Court Judge Derrick Watson wasn't buying it

"The remarkable facts at issue here require no such impermissible injury," he replied on Wednesday, saying "there is nothing 'veiled' about the (Trump campaign's December 2015) press release: 'Donald J. Trump is calling for a total and complete shutdown of Muslims entering the United States.'"

JUST WATCHED Donald Trump: Ban all Muslims from entering U.S. Replay More Videos ... MUST WATCH Donald Trump: Ban all Muslims from entering U.S. 02:28

Even benches with a more favorable take on the administration's legal argument, take a dim view of Trump's public response to prior setbacks. In an unsolicited filing delivered late Wednesday, five GOP-nominated judges went on the record declaring, "Whatever we, as individuals, may feel about the President or the Executive Order, the President's decision was well within the powers of the presidency."

Still, they felt compelled to register their discontent with Trump's "personal attacks" on US District Court Judge James Robart after his February decision to temporarily stop the ban.

"Such personal attacks treat the court as though it were merely a political forum in which bargaining, compromise, and even intimidation are acceptable principles," the judges wrote. "The courts of law must be more than that, or we are not governed by law at all."