The U.S. Senate seat that will soon be vacated by retiring Sen. Pat Toomey, R-PA, is one of the most-watched races in the country. The dynamics in play: the delicate political balance of the US Senate and historic spending. To date, the Republican candidates are said to have spent over $55 million in the Primary alone.

At the time of writing, unofficial results have former President Trump-backed Dr. Mehmet Oz leading the race with a razor-thin margin of 31.2 percent over hedge fund CEO David McCormick with 31.1 percent (which translates to a mere 1,127 votes) – but those numbers could continue to shift as mail-in ballots, provisionals, and military and overseas votes continue to be counted. The margin is well below the trigger, of 0.5 percent, for a recount. The recount process will begin on June 1 and must conclude by June 7, pending further (and expected) legal challenges.

On the Democratic side, sitting Lt. Gov. John Fetterman – who suffered a stroke just days before the Primary and was recovering in a hospital for the week following Primary Election Day following a pacemaker insertion – won with 59 percent of the vote, well ahead of his closest opponent, Congressman Conor Lamb.

The general election contest between Fetterman and whomever prevails for the GOP will be among the most competitive and expensive in the nation. Cook Political Report currently rates the race as a toss-up.

Downballot, a number of congressional races in the state, particularly in the suburbs of Philadelphia, Pittsburgh and the Lehigh Valley, are expected to be competitive, in part due to redrawn districts following the state losing a seat with reapportionment. The PA Chamber will watch these races closely, as their outcomes will help shape the balance of power in D.C. next year.