Maggie Astor for the NYT:

A few weeks ago, Representative Dan Crenshaw, a Texas Republican, falsely claimed that the centerpiece of President Biden’s domestic agenda, a $1.75 trillion bill to battle climate change and extend the nation’s social safety net, would include Medicare for all.

It doesn’t, and never has. But few noticed Mr. Crenshaw’s lie because he didn’t say it on Facebook, or on Fox News. Instead, he sent the false message directly to the inboxes of his constituents and supporters in a fund-raising email.

Lawmakers’ statements on social media and cable news are now routinely fact-checked and scrutinized. But email — one of the most powerful communication tools available to politicians, reaching up to hundreds of thousands of people — teems with unfounded claims and largely escapes notice.

The New York Times signed up in August for the campaign lists of the 390 senators and representatives running for re-election in 2022 whose websites offered that option, and read more than 2,500 emails from those campaigns to track how widely false and misleading statements were being used to help fill political coffers.

Both parties delivered heaps of hyperbole in their emails. One Republican, for instance, declared that Democrats wanted to establish a “one-party socialist state,” while a Democrat suggested that the party’s Jan. 6 inquiry was at imminent risk because the G.O.P. “could force the whole investigation to end early.”

But Republicans included misinformation far more often: in about 15 percent of their messages, compared with about 2 percent for Democrats. In addition, multiple Republicans often spread the same unfounded claims, whereas Democrats rarely repeated one another’s.

At least eight Republican lawmakers sent fund-raising emails containing a brazen distortion of a potential settlement with migrants separated from their families during the Trump administration. One of them, Senator John Kennedy, Republican of Louisiana, falsely claimed that President Biden was “giving every illegal immigrant that comes into our country $450,000.”