While Republicans are giddy about their chances for regaining the House next year, GOP prospects for taking the Senate remain more uncertain, data reviewed by Axios suggests.

By the numbers: At least five Republican senators are retiring after the midterms, and four of their seats are in battleground states. That makes a simple Republican-for-Republican election exchange all the more difficult.

• All told, 20 Republican seats are among the one-third of the Senate up for reelection.
• Meanwhile, none of the 14 Democratic senators up for reelection have announced retirement plans.
• Four of their seats — in Georgia, New Hampshire, Arizona and Nevada — are being targeted by the GOP.

How it works: Axios has used a headshot to chart every candidate whose state was decided in the 2020 presidential election by 15 points or less.