The president mentioned the issue most recently on February 9 in a meeting with a group of senators when he repeated that he would have won the state of New Hampshire had there not been "thousands" of people "brought in on buses" from neighboring Massachusetts to "illegally" vote in the state, Politico reported.
Speaking to George Stephanopoulos on ABC on Sunday, Miller said the White House has provided "enormous evidence" of the fraud, though so far this evidence has only come from assertions of the president's "belief" and from either inaccurate or misrepresented reports.
In asking Miller specifically about Trump's claims of voter fraud in New Hampshire, Stephanopoulos pointed out that Trump and the White House team have provided no evidence for their claims.
A morning news show is not the venue for evidence to be laid out, Miller said. But having worked on campaigns in New Hampshire, "I can tell you that this issue of busing voters in to New Hampshire is widely known by anyone who's worked in New Hampshire politics," he said. "It's very real; it's very serious."
Pressed again for evidence, Miller contended that, "Many, many highly qualified people have looked deeply into this issue and found it to be true."
"I can tell you this, voter fraud is a serious problem in this country," Miller said. "You have millions of people who are registered in two states; who are dead and who are registered to vote," as well as noncitizens registered to vote.
He suggested Stephanopoulos, rather than asking the administration to provide any solid basis for their frequent assertions, "talk to anybody who's worked in politics" in New Hampshire for evidence.
Though not asked, New Hampshire Senator Jeanne Shaheen offered her take on Twitter.
— Sen. Jeanne Shaheen (@SenatorShaheen) February 12, 2017
"Nobody disputes" that widespread voter fraud is an American crisis, Miller declared. "Dead people voting, non-citizens being registered to vote: George, it is a fact and you will not deny it that there are massive numbers of non-citizens in this country who are registered to vote."
Miller also said he would be happy to repeat the Trump team's unsubstantiated claims anywhere, at any time.
"As a country we should be aghast about the fact that you have people who have no right to vote in this country registered to vote, canceling out the franchise of lawful citizens of this country. That's the story we should be talking about. And I'm prepared to go on any show, anywhere, anytime, and repeat it and say the president of the United States is correct, 100 percent." But not, apparently, to provide any backing for the administration's claims.
Trump's own voter fraud expert, Greg Phillips, was found last month to be registered to vote in multiples states, as well as one of his daughters, his son-in-law, and members of his staff.
Federal Elections Commission member Ellen Weintraub asked on Friday for the president to present some kind of evidence for his claims.
— Ellen L Weintraub (@EllenLWeintraub) February 10, 2017
He so far has not. Nor has the president made an order investigating the much-discussed voter fraud one of the many executive orders he's signed since taking office.