2020 Democrats may have found their common enemy — and it's not President Trump.

Last week, former congressmember and Senate candidate Beto O'Rourke joined the wide field of Democrats aiming for the presidency. But instead of Trump using O'Rourke's increasingly popular name to rile up his fans, it was actually fellow Democrats who started shoving "Beto" into their fundraising email subject lines.

Sen. Elizabeth Warren (D-Mass.) was one of the first Democrats to welcome O'Rourke into the race, firing off a very kind email complete with an exclamation point. But she quickly pivoted, pointing out that "more candidates" could easily mean less support for her, so you should donate and show "you're with Elizabeth." Sen. Kamala Harris (D-Calif.) was a little more blunt, pointedly naming O'Rourke when she said she wanted to "engag[e] in substantive debates" with the extra-large 2020 pool and using just O'Rourke's name in the subject line.

Yet it was Sen. Bernie Sanders (I-Vt.) who had the harshest dig, acknowledging in a Monday email that yes, O'Rourke crushed Sanders' 24-hour fundraising record. But you know what, "we more than likely had a lot more individual donations than he did," Sanders' email sassily continued.

Sanders’s campaign sends a fundraising email just now noting Beto’s haul. It ends: “The first FEC report is going to send a message about who is the best candidate to beta Trump. So we’re looking to report as many insidious all donations as we possibly can.” pic.twitter.com/SnBdNvo2eX — Lauren Gambino (@laurenegambino) March 18, 2019

Even if Democrats aren't necessarily pointing out O'Rourke as an enemy, it's pretty clear using his name as a subject line gets clicks, New York Magazine's Gabriel Debenedetti points out. And of course, throwing an extra layer of drama into the fundraising scramble doesn't hurt either. Kathryn Krawczyk