1. Pennsylvania
Incumbent: Republican Pat Toomey (retiring)
2. Georgia
Incumbent: Democrat Raphael Warnock
3. Wisconsin
Incumbent: Republican Ron Johnson
4. North Carolina
Incumbent: Republican Richard Burr (retiring)
5. Arizona
Incumbent: Democrat Mark Kelly
6. Nevada
Incumbent: Democrat Catherine Cortez Masto
7. New Hampshire
Incumbent: Democrat Maggie Hassan
8. Ohio
Incumbent: Republican Rob Portman (retiring)
9. Florida
Incumbent: Republican Marco Rubio
10. Missouri
Incumbent: Republican Roy Blunt (retiring)
I think the GOP can take all 10.