Oz and McCormick neck-and-neck in Pennsylvania's GOP Senate primary

• Kathy Barnette, an "ultra-MAGA" candidate, appears to have come in third place, as her campaign fizzled out following a sudden rise in the polls ahead of Tuesday's election.

State of play: The election may not be called for days. Printing errors on thousands of mailed ballots in Republican-leaning Lancaster County will delay the counting of those votes, according to the Associated Press.

• Plus: It could go to a recount, should the margin between the top two candidates be half a percentage point or less, per state law.

Details: Pennsylvania law says a recount must be scheduled by the third Wednesday after Election Day.

• In this case, that process would have to start by June 1 and be completed by June 7, per the Philadelphia Inquirer.

By the numbers: The contest to replace retiring Republican Sen. Pat Toomey has become one of the most expensive U.S. Senate races in the nation, with millions of dollars contributed from across the country.

• Oz funneled at least $12 million of his own wealth into his campaign, and McCormick spent at least $11 million, according to Federal Election Commission filings.

Between the lines: If Oz secures the Republican ticket, it could indicate the continued power of Trump's endorsement in this year's midterm cycle.

• Oz would become the first Muslim elected to the Senate.

What to watch: The winner will face off against Lt. Gov. John Fetterman, who won the Democratic nomination, in November.