Donald Trump wore those words out as a candidate as he beseeched voters to buy into his grand plans and promises on everything from crushing ISIS to building a great border wall.

Now, the question of whether Americans can trust Trump is again a dominant political theme after he was caught in a lie over claims that he was wiretapped by his predecessor Barack Obama.

Trump's repudiation by FBI Director James Comey in a sensational hearing Monday came exactly two months into an administration unusually prone to obfuscation, blurring facts and peddling falsehoods.

From false assessments of the size of his inaugural crowd and claims that millions of illegal voters dealt him defeat in the popular vote in November, the President has often seemed happy to propagate conspiracy theories.

While such tactics helped Trump in the circus of a presidential campaign unfolding in a new era of post-truth politics, it's less clear that trading in untruths -- by setting up the press and the intelligence agencies as a foil for his confrontation brand of politics -- is a recipe for a successful presidency.

If upcoming opinion surveys emulate a Gallup tracking poll in showing Trump's approval rating slipping below 40% , it could indicate that the President's recent trials are having a tangible political impact.

A growing credibility gap could be hard for Trump to reverse, and squandering the trust of the American people could even be dangerous, given that he may need to rally the nation at a moment of national crisis or foreign policy peril.

"Americans naturally, and it's a good characteristic, do rally around their bald eagle, their president, in times of crisis," CNN presidential historian Timothy Naftali said.

"But Americans also are impatient. If they don't see results and if they don't have a well of trust in the person who is leading, that period of unity doesn't last very long."

"What I worry about at the moment is that because President Trump has shown such disrespect of the US national security community, including the intelligence community, it is hard for me to see how he can convince the American people of anything less than an absolute in your face threat," Naftali said.

Of course, Trump is not the only President to shade the truth.

Most recently, Obama, when selling Obamacare, told Americans that if they liked their doctor they could keep their doctor. President George W. Bush convinced the country that Saddam Hussein had weapons of mass destruction. And Bill Clinton lied about sex with a White House intern.

But none come near Trump in the volume of their falsehoods: the Pulitzer Prize-winning website Politifact, on its Truth-o-Meter monitor, currently rates a staggering 70% of the President's statements as mostly false, false or "pants-on-fire."

Just this week, Trump stated incorrectly that Germany owes "vast" sums of money to NATO. During the Comey hearing, his official presidential Twitter account falsely said that the FBI chief and his National Security Agency counterpart Mike Rogers testified that Russia had no influence on the electoral process. Both men later rejected that assertion during the hearing. They had actually originally testified that no votes were changed by Russia's operation and did not say that Moscow's spies had not influenced the wider election process.

Trump's tendency to play loose with the facts is mirrored by his subordinates.

On Monday for instance, his spokesman, Sean Spicer, said that former Trump campaign chairman Paul Manafort, who is caught up in the flap over links between Trump aides and Russia, played a 'limited role" in the campaign. In fact, Manafort was for a time campaign chairman, and ran Trump's delegate operation and worked for him between March and mid-August last year.

On "Fox and Friends," Trump White House aide Kellyanne Conway was asked Tuesday about the President's relationship with former campaign aides including Carter Page, who met Russian officials.

"I have spoken directly to the President and other senior officials about this," Conway said. "He doesn't know these gentlemen. He didn't work with them."

That statement seemed to contradict Trump's own statement to The Washington Post editorial board in March 2016 when he named Page as a foreign policy aide.

Democrats see an opening

In a blunt editorial that appeared online on Tuesday night, The Wall Street Journal rebuked Trump for not withdrawing his accusation against Obama and warned such controversies could damage his White House.

"Two months into his presidency, Gallup has Mr. Trump's approval rating at 39%. No doubt Mr. Trump considers that fake news, but if he doesn't show more respect for the truth, most Americans may conclude he's a fake President," the editorial said.

Comey's announcement that the FBI was pursuing an investigation into links between Trump campaign aides and Russia is likely to exacerbate questions of trust around the administration.

The President's enemies sense an opening: Democratic Minority Leader Chuck Schumer complained Tuesday it would be wrong to confirm Trump's Supreme Court pick Judge Neil Gorsuch "while this 'big, gray cloud' of an FBI investigation hangs over the presidency."

Trump's self-inflicted problems seem to be increasingly irking his Republican allies. Asked Tuesday whether there were doubts about Trump's credibility, Senate Republican Majority Leader Mitch McConnell replied: "You can ask the White House a question like that."

It's not surprising that questions of trust are so dominant in politics since last year's election turned on widespread, bipartisan disdain for the political process and Washington establishment.

Democratic presidential nominee Hillary Clinton argued that Trump's volatile temperament meant he could not be trusted with the nuclear codes -- and she won the popular vote.

But Trump got sufficient voters to buy into his narrative that " Crooked Hillary " could not be trusted -- and won the Electoral College and the White House.

But it will take more than a rebuff from the FBI to test Trump's bond with his loyal supporters.

In fact, his public battles with once-trusted bastions of power like the intelligence agencies, the press and the bureaucracy may solidify his bond with his core vote.

The question of how far Trump could be trusted were central to a riveting day of political drama Tuesday.

'We are going to keep our promises'

The President traveled to Capitol Hill to build bridges with GOP lawmakers, some of whom are holdouts on the Obamacare repeal bill.

He put on what Republican Rep. Tom Cole called a "vintage" and "direct, colorful, funny, persuasive and pointed" show.

Trump also played the trust card himself, arguing that GOP voters had believed promises that lawmakers would repeal Obamacare.

"The President was really clear. He laid it on the lines for everybody," House Speaker Paul Ryan said. "Now's our time to keep that promise ... people will reward us. If we don't keep that promise, it will be very hard to manage this."

If jittery lawmakers were still ambivalent in placing their trust -- and perhaps their political fate -- in the hands of Trump, they might have cast a glance to the other side of the Capitol.

There in a Senate hearing room sat the personification of a presidential promise kept.

Many conservatives were leery when Trump promised to nominate a judge in the image of late Antonin Scalia for the Supreme Court -- but trusted him -- and he repaid them with Gorsuch, who looks likely to win confirmation after navigating the second day of his confirmation hearing.

South Carolina Sen. Lindsey Graham jokingly referred to the dilemma conservatives faced in the hearing on Tuesday as he praised Trump for the nomination: "Quite frankly, I was worried about who he would pick -- maybe someone on TV!"

Trump lauded Gorsuch as a promise fulfilled in a reunion with caucus supporters at a campaign rally in Kentucky on Monday night -- in which he showed a fixation with maintaining the trust of his voters.

"We are going to keep our promises, all of the promises that we made," Trump said.

The event, and Trump's other recent communions with supporters, were a sign that he understands that given his comparatively thin support base, he cannot afford to lose any of the people who trusted him most.

Yet building a successful presidency might require broadening his outreach, a task Trump has so far been unwilling to attempt.

Still he was quiet on the wiretap saga -- in person and on Twitter -- following the conclusion of Comey's hearing, perhaps a sign that he wants to move ahead.

But he has some catching up to do.

"I think it would be a mistake to say categorically declare that would be impossible for Donald Trump recover trust with some of the people who are against him now," said Naftali, who teaches at New York University. "Those who keep predicting a change in his rhetoric have been proven wrong time and again. (But) with an approval rating below 40% the President will at some point understand that is not actually enough support to fundamentally reorder the the US government, which is his stated objective."