September brings a turn into the homestretch of a key midterm election, with control of both houses of Congress hanging in the balance. September 12 features marquee primaries—none more central to the GOP’s Senate majority than that between Rhode Island’s Lincoln Chafee, the body’s most liberal Republican, and Stephen Laffey.

It’s a tough year for in cum bents already: Senator Joe Lieberman lost a challenge from the left in Connecticut, and Rep. Joe Schwarz lost a challenge from the right in Michigan.

Here’s a rundown on Chafee’s reelection efforts:

1. “Linc” Chafee was born to politics, but he was late to get into the game. A Brown grad and son of the late senator John Chafee, he spent his young adulthood shoeing harness-racing horses in western Canada and elsewhere. After entering politics in his thirties, he was appointed to the Senate upon his father’s death in 1999. Long gone from the tracks of Calgary, Chafee still loves to recite the homespun lessons from his life as a farrier.

2. Steve Laffey, too, took a roundabout route. A working-class kid, he won scholarships to Bowdoin College and Harvard Business School and made his fortune at a Memphis securities house—a career path that made him the kind of capitalist who could get the antitax Club for Growth, led by Rhode Island native Pat Toomey, to back his challenge. The group has helped Laffey raise money and make this the most competitive GOP Senate primary Rhode Island’s ever seen.

3. The GOP primary may be a classic personality clash—the soft-spoken, liberal-leaning Chafee versus the brash, more conservative Laffey. But both contestants have been small-city mayors in challenging situations—Chafee in Democratic-led Warwick, Laffey in nearly bankrupt Cranston.

4. Former state attorney general Sheldon Whitehouse is expected to take the Democratic primary in a walk—although political newcomer Carl Sheeler grabbed attention for his billboards that read impeach bush.

5. Rhode Island values pedigree in senators. Chafee’s father was an avatar of temper ate Republican WASPs from the Northeast. Whitehouse is not only a certified blue blood; his father was John Chafee’s roommate at Yale and lifelong friend, the late diplomat Charles Whitehouse.