Rich people are spending more than ever to run for Congress. A big test is coming in Maryland.

Wealthy office-seekers plowed more of their own money than ever into runs for Congress last year. Now, the biggest one of all is facing an important hurdle.

Democratic Rep. David Trone has given more than $57 million of his own money to his campaign for Senate in Maryland ahead of next week’s primary — a staggering sum that already ranks among the biggest self-funding campaigns in U.S. history. But he’s not alone: Self-funding congressional candidates gave more to their campaigns in 2023, $131 million, than in any other odd year going back to at least 2003, according to an NBC News review of campaign finance records.

Led by nearly $37 million from Trone last year alone, it’s part of a recent explosion of spending by wealthy candidates that has fundamentally shifted the way campaigns are won and lost — and perhaps made it harder than ever for the non-rich to make it to Washington, since candidates are not bound by donation limits and can give unlimited sums to their own campaigns.

The trend is affecting everything from open-seat primaries for deep red or blue districts across the country to the battle for the Senate. Trone continues to spend heavily — including on ads featuring prominent endorsers like state Attorney General Anthony Brown —as he looks to win the Democratic primary for retiring Sen. Ben Cardin’s seat, before what’s expected to be a costly November battle against former Republican Gov. Larry Hogan. Also running hard for the Democratic nomination is Angela Alsobrooks, the Prince George’s County executive who has won support from some of Maryland’s most prominent Democrats — but has been outspent 9-to-1 by Trone.

“I don’t believe this is the way democracy works. I believe we should have reform in these