Gov. Wes Moore, a Democrat, has begun running ads on Fox News that promote Dan Cox, a Republican running in a contested primary to challenge him.

The main super PAC tied to the influential American Israel Public Affairs Committee released its first ads backing Ms. Stevens, a moderate congresswoman locked in a tight three-way primary.

Chuck Schumer, the Democratic minority leader, has remained officially neutral on the race, but in conversations with donors, he has been clear about which candidate he supports.

Dr. Adam Hamawy, a New Jersey Democrat with big-name support on the left, has touted his humanitarian work, but some opponents want to talk about Sheikh Omar Abdel Rahman.

One is allied with Anthropic. The other is tied to OpenAI. They’re both spending millions to influence the midterms, and they’re leaving a trail of fearful candidates and canceled ads in their wake.

Social media stars have become a magnet for campaigns and political groups that want to push priorities without disclosing where their money is going.

In strikingly different ads, Graham Platner argued that “Susan Collins’s charade is over” while Senator Collins highlighted the economic benefits she has brought to Maine.

Republicans have built a small advantage from the gerrymandering clash so far, but Virginia voters could change that.

The left is creating new, obscure nonprofits to funnel hundreds of millions of dollars into politics and advocacy.

Gov. Janet Mills argues that her rival for Senate, Graham Platner, could be doomed by his history of offensive online remarks. But at a time of anti-establishment anger, Mr. Platner says he is the safer choice.

Democratic voters put Lt. Gov. Juliana Stratton on a path to the Senate, while the pro-Israel lobby notched its first major victories of the year but also faced a tough defeat.

All across America, congressional candidates are finding creative — and critics say cynical — ways to signal support for two deep-pocketed industries, A.I. and crypto.

Ahead of Tuesday’s vote, the Democratic and Republican races have become increasingly personal and contentious.

“Donald Trump has 99 problems going into the midterms,” one Democratic strategist said. “But money ain’t one.”