A GOP gain of five seats would effectively split the 100-member Senate between the two parties, instantly elevating the vice president's role as the 101st senator. That would raise Biden's own profile heading into 2016, when the former Delaware senator has said he may run for president again.
"It makes Joe Biden suddenly a hugely relevant Washington figure," said Douglas Brinkley, a presidential historian at Rice University. "It shows he's a power player."
On the other hand, it could make Biden the face of messy political fights on Capitol Hill, potentially alienating some voters along the way.
Biden spent nearly four decades steeped in the chamber's tradition and camaraderie, and a high-profile return would allow him to show former colleagues he's still in the game.
Some questions and answers about what happens if the Senate splits in November:
HAS IT EVER HAPPENED BEFORE?
Yes, but only a handful of times. The first was under President James Garfield in 1881, when a special session expected to last just 11 days stretched into 11 weeks as the Senate deadlocked, according to the Senate Historical Office.
A split Senate didn't occur again until 1953, when Republican Majority Leader Robert Taft died and was replaced by a Democrat, leaving Vice President Richard Nixon as the would-be tiebreaker until other deaths gave Democrats the majority.
The Senate was split 50-50 following the 2000 elections, giving Democrats majority control for 17 days beginning Jan. 3, 2001, because Al Gore was still vice president. Republicans gained power Jan. 20 when Dick Cheney was sworn in as George W. Bush's vice president.
As president of the Senate, the vice president gets to cast the tie-breaking vote regardless of which party controls the Senate. But 50-50 ties are much more likely when the Senate's membership is evenly split.
There have been nearly 250 tie-breaking votes cast by vice presidents in U.S. history, but none by Biden. The most recent came in 2008, when Cheney cast the 51st vote for a budget amendment on the alternative minimum tax.
WHAT ARE THE CHANCES OF A TIE THIS YEAR?
Republicans would need a net gain of five seats in November, but with Obama's unpopularity dragging his party down, Democrats are bracing for even greater losses. Democratic hopes for averting a GOP majority rest in places like Alaska, Arkansas, Georgia, Kentucky, Louisiana, New Hampshire and North Carolina — conservative-leaning states tough for Democrats to defend.
Even if the Senate deadlocks, it wouldn't technically be a 50-50 split. That's because there are two independents. Both caucus, or meet, with Democrats, so they're counted as Democrats in determining which party has the majority.
There's a chance, though, that one of them could switch allegiances if the GOP wins the majority.
Two more independents could win seats this year. In Kansas, Greg Orman has said he would caucus with whichever party wins the majority, while in South Dakota, former Sen. Larry Pressler has been coy about his intentions.
SO WOULD BIDEN BE CALLED UPON TO VOTE ON EVERY BILL?
Only votes that are deadlocked require the vice president to weigh in. These days, parliamentary maneuvering has raised the threshold to pass almost anything to 60 votes, the number needed to overcome a filibuster.
An even balance of power might create an opening for Biden to act as a broker behind the scenes, showing him as a pragmatist who can work with both parties. But if Biden gets called in to swing the vote on a controversial Obama-backed policy — an immigration bill, for example — Republicans would likely use that vote against him.
Place home." She added that Casablanca is a short course and was in much better condition.
"Our weight and conditioning has shown positive outcomes. These kids have skill, but my emphasis was also to instill the proper mindset to go and compete."
"These kids now know that through hard work, persistence, repetition and a positive attitude anything is possible."