“The bulk of my research is looking at US House primaries, and I think you could probably draw similar conclusions for Senate primaries, except that in most cases, Senate primaries have way more information. So in the case of Michigan, I think people knew largely what the choices were. And after you get to that stage, largely through money and advertising and voter outreach, and campaigning, after that point, money might matter less because voters become more familiar with choices. But this is a really steep hurdle in most congressional primaries.

“Karoline will now be one of my top outside advisors, and an influential voice within the Republican Party

“200 Democrats are running for reelection in primaries and almost every one of them had a younger challenger

“So I’ve learned that fully self-funded candidates, meaning those who don’t supplement with financial support from others, typically lose. Self-funding on its own is not as valuable as getting money from others, and in particular large-dollar donations from others.

“When I go into a state and headline a fundraiser for one of my colleagues, it seems to attract people

“I think that people forget how low information these contests usually are. Many primary voters really don’t know much about candidates. I think in the Michigan Senate example, that was less true. Money isn’t irrelevant, but when you have other pieces of information, that can override money. And furthermore, in that case, both of the candidates were spending millions of dollars in the primary. I mean, this is just so unique in a lot of ways.

“As the most powerful Republican in state government, Demuth used her narrow share of power in the tied House to secure spending cuts, repeal state health care coverage for undocumented adults and block gun control measures.

“she's a registered Democrat mostly to participate in primaries