A bloc of Trump voters in key swing states also backs Democratic Senate candidates. Here’s why that matters.

But in that same poll, Democratic Sen. Sherrod Brown had a four-point edge over Moreno among likely voters (47% to 43%). Brown also won over 13% of Republicans in the poll, a level of crossover support that helps him in the red-trending state.

The Times/Siena poll also showed Democratic Rep. Ruben Gallego leading Lake by six points (49% to 43%) in Arizona. In Michigan, Democratic Rep. Elissa Slotkin led Rogers by five points (47% to 42%). And in Pennsylvania and Wisconsin, Sens. Bob Casey Jr. and Tammy Baldwin led their GOP opponents by nine and seven points among likely voters, respectively.

Why does this matter?

Should Democrats run the table in the most competitive swing-state Senate races, it’ll leave them on the cusp of holding on to a majority.

For Democrats, winning both safe and swing-state races — along with Ohio — would get the party to 49 seats. Then they’d need Montana Sen. Jon Tester to win reelection to get to 50 seats. (Tester is currently locked in a tough reelection battle against Republican Tim Sheehy in a state that Trump is expected to win by double digits.)

Democrats are now trying to expand their Senate map by investing more money in Florida and Texas, which lean Republican on the presidential level but are poised to have close Senate races.

Holding a majority is the best-case scenario for Harris should she win the election, as she would need a Democratic-led Senate to not only move through most of her agenda but also approve the bulk of her judicial appointments.

If Harris wins in November and Democrats win exactly 50 seats, then Minnesota Gov. Tim Walz would deliver a majority by virtue of the vice-presidential tie-breaking abilities.

And Democrats would be able to thank some of Trump’s voters for that.

But should Trump win the election and pro-Trump ticket-splitters help Democrats keep their majority, it would pump the brakes on a conservative agenda.

A Democratic Senate would serve as a check on Trump. If Democrats flip the House, that chamber would be another check on him. And even if Republicans keep the House in a potential Trump second term, they’d clash with a Democratic-led Senate on a range of issues.

So ticket-splitters who are backing Trump now have the potential to become one of the most important voting blocs of the 2024 election.