What happens if there’s a tie in the party makeup of the Senate?

As in, 50 Democrats, 50 Republicans, and no clear majority. What happens then?

The Senate Health Care Process OF DOOM

Or more specifically, “How the hell were McConnell and the Senate Republicans allowed to pull all of that bullsh*t during their ACA repeal-and-maybe-replace budget reconciliation process?”

Quick Q&A: Can you force the Senate to require a two-thirds majority instead of a simple majority?

AKA, everything you may have wanted to know about Senate voting rules but didn’t really care enough about to ask.