One plus of US elections is they are pretty decentralized.

I've seen some post election conspiracy theories floating around. It is pretty hard to rig American elections at scale.

Most states do post-election audits. These audits typically examine the tabulators and voting machines and their paper trail. The vast majority of votes in US elections have a paper trail, whether by paper ballot or machine.

They'll sample ballots depending on the audit method and check for any issues.

Election officials also do a vote canvassing where they reconcile the poll books with the actual ballots cast. That way they can verify if the vote totals actually are accurate.

For the same reason Trump was wrong about 2020, mass fraud in 2024 would also be detected.