Whether it's because of his own conspiratorial mindset, a desire to keep political loyalists engaged or a lack of interest in dry policy details, Trump frequently acts to address an idiosyncratic version of reality.

On immigration in particular, but also on gender issues or electoral reform, Trump has often waded in to tackle what he bills as a national emergency that few other people see.

Trump's announcement Thursday that he wants to send " anywhere from 2,000 to 4,000" National Guard troops to the southern border , following a week of rising fury on the issue of immigration, is a prime example of how his oft-challenged beliefs drive government policy.

Also on Thursday, he revived one of his most notorious and misleading claims , the idea that Hillary Clinton's win of the popular vote in 2016 was the result of massive fraud.

He claimed that many people in the Democratic bastion of California voted many times, portraying the state of the electoral system as a grave national crisis.

"They always like to say, 'Oh that's a conspiracy theory.' It's not a conspiracy theory.' Millions and millions of people, and it's very hard because the state guards their records," the President said.

The problem is that there is no evidence to support his claims, and even a commission set up by the White House ended up failing to prove Trump's portrayal of events that would represent an existential crisis for American democracy if they were true.

The border 'crisis'

In no area has Trump been so willing to create his own version of reality as on immigration policy, a topic that more than any other electrified his base and propelled him to the White House.

The decision to deploy the National Guard came in a week when he consciously stoked the flames of crisis, apparently set off by a Fox News report Sunday, about a "caravan" of Central American refugees trekking across Mexico toward the US border. With midterm elections looming, he's been taking fire from conservative media disappointed with his failure to do more, let alone build his signature border wall.

The White House billed the National Guard move as a last-ditch step to stem a torrent of people and drugs across the border in the face of congressional inaction. But it actually comes after a period of historically low transgressions -- despite a rise in crossings in March -- a fact that the President previously celebrated.

But it's not clear that sending the National Guard to the border, as his predecessors Barack Obama and George W. Bush both did on occasion, is a proportionate response to the current situation.

After all, members of the caravan actually want to get swept up by border authorities because they plan to apply for asylum, so they are unlikely to try to evade capture. Anyway, they represent the hordes of aliens descending on US borders that might merit a military response.

Indeed, critics of the border wall project itself say it addresses a problem that does not exist, and it would not deal with one of the most pressing immigration issues: the number of people who enter the country legally and then overstay their visas.

Trump's missing landslide

Trump's claims on voter fraud seem to be the fruit of a conspiratorial mind.

It all started even before he took office, when Trump made clear he wasn't satisfied with simply winning the White House via the Electoral College -- he wanted to establish that Clinton hadn't won the popular vote. Although Trump beat Clinton by 306 to 232 electoral votes , the Democrat outpaced him in the popular vote by almost 2.9 million votes.

"In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally," Trump wrote in a tweet in November 2016 that caused shock, bafflement and even derision.

In addition to winning the Electoral College in a landslide, I won the popular vote if you deduct the millions of people who voted illegally — Donald J. Trump (@realDonaldTrump) November 27, 2016

In an apparent attempt to spare the President's blushes, the administration eventually set up a commission to probe voter fraud in the 2016 election, on which Vice President Mike Pence was a key member.

Perhaps not surprisingly, the commission was dissolved after failing to produce any evidence, though Trump blamed the move on the failure of several states to cooperate.

But as with the current row over immigration, Trump opponents saw not just an attempt to indulge the President's prejudices at work, but also an attempt by Republicans to make it harder for minorities -- a key Democratic constituency -- to vote.

"The mere mention of voter fraud is a dirty tactic to suppress voters and turn people off from participating in elections. This undermines the public trust in our election system," said Chris Carson, president of the League of Women Voters.

Travel ban

One of the first big battles over immigration last year erupted after Trump announced plans to bar visitors from a number of mainly Muslim nations in what he said was an effort to thwart Islamic terrorists from infiltrating US soil.

We need a TRAVEL BAN for certain DANGEROUS countries, not some politically correct term that won't help us protect our people," Trump tweeted on June 5, 2017, months after the original iteration of the travel ban executive order was blocked in the courts.

One logical problem with the travel ban, modified after several court challenges, was that if it was meant to stop terrorism, it was directed against the wrong people.

Many national security experts believe that the biggest threat to US shores from foreign-born terrorists is represented by those who can get into the United States under the visa waiver program covering European and other nations.

Still, as a political device, new versions of the travel ban, which is still being challenged in various courts, allowed Trump to deliver on his campaign promises to get tough on terrorism, even if it was not the most appropriate way to combat the threat.

Transgender troops

In a classic in his long history of volcanic tweets, the President set off a huge controversy last July by announcing that he would bar all transgender individuals from serving in the nation's armed forces.

"Our military must be focused on decisive and overwhelming victory and cannot be burdened with the tremendous medical costs and disruption that transgender in the military would entail," Trump wrote.

Yet his move appeared to catch the military off guard, since there was no plan in place to put the commander-in-chief's order into action.

It also appeared to be another attempt by Trump to solve a crisis that many of those involved did not believe really existed.

On the issue of medical costs, for example, a Rand Corp. study released earlier this year debunked the idea that transgender troops represented a huge burden because of gender transition therapy.

Rand found that medical costs for transgender personnel would be between $2.4 million and $8.4 million a year -- less than a quarter of 1 percent of the value of all health care costs for people on active duty.

This week, the largest association of doctors in the US took aim at Trump's other claim: that transgender troops could harm the morale and effectiveness of US armed forces.

As with other fronts in Trump's war on nonexistent crises, there is also a political explanation.

In March, the administration formalized the President's decision barring people with a "history or diagnosis of gender dysphoria" from serving in the military except in limited circumstances.

The policy, popular with evangelical groups vital to the President's electoral coalition, happened to come out at a moment when Trump was under extreme political and legal pressure over lawsuits brought by women who claimed they had had affairs or had been sexually harassed by him.