Where’s the beef?

The burden of proof is on the prosecution. So if President Trump is going to make damaging accusations about Massachusetts voters pouring over the border to vote illegally in New Hampshire — enough to tilt the New Hampshire outcome in favor of Hillary Clinton — then the White House must produce evidence to support the claim.

Not only hasn’t it provided any evidence that “thousands” of Massachusetts voters were bused in to vote illegally, as Trump told some Democratic senators, but a senior aide has suggested it really doesn’t need to. “Everybody’s aware” of a fraud problem in New Hampshire, senior policy adviser Stephen Miller said on ABC Sunday. Oh, well, if he says so.

Now, we have long opposed the policy in New Hampshire that allows voters to register to vote and cast a ballot on election day — something progressive groups are pressing to bring to Massachusetts. There is both the risk of fraud as well as the questionable value in accommodating voters who couldn’t be bothered to sign up in advance.

But even if one assumes that

all those who registered without proof of residency and cast ballots on election day in New Hampshire did so fraudulently, it wouldn’t erase the 2,732 vote margin that favored Clinton. Secretary of State William Gardner said of the letters sent to 1,124 voters to confirm residency after the fact, about 100 were returned as undeliverable; about 600 haven’t yet responded and the rest it seems were legit.

And if the only evidence that Trump supporters have to back their claims is the presence of cars with Massachusetts license plates parked at polling places, that suggests an astonishing ignorance of how things work around here. The Massachusetts outcome was never in doubt (it rarely is) so true blue activists headed north to hold signs, knock on doors and help out at phone banks for their candidate of choice.

What the White House is alleging in New Hampshire (and nationwide for that matter) would amount to a massive criminal conspiracy. But Trump continues to be the president who cried wolf. The Republican Congress ought to call him on it.