An automatic recount has been triggered in the U.S. Senate race in Pennsylvania between Bob Casey and Dave McCormick. Here's how the recount will work.

The tight margin in the Senate race between Sen. Bob Casey, D-Pennsylvania and Republican Sen.-elect Dave McCormick has triggered an automatic recount under Pennsylvania law.

A small margin in votes separating incumbent Democratic Sen. Bob Casey from Republican challenger David McCormick Jr. has triggered a recount in the Pennsylvania Senate race, the commonwealth's secretary said Wednesday.

Pennsylvania’s Senate race is heading towards a recount between Republican Dave McCormick and Democratic Sen. Bob Casey. NBC News’ Mark Murray reports.

The incredibly tight Pennsylvania race between Democratic Sen. Bob Casey and Republican challenger Dave McCormick will head to a recount, Pennsylvania Secretary of the Commonwealth Al Schmidt announced Wednesday.

The U.S. Senate election in Pennsylvania between Democratic incumbent Sen. Bob Casey and Republican David McCormick is headed for a statewide recount, as counties continued Wednesday to sort through outstanding ballots and the campaigns jousted over which ones should count.