Across two states with Republican-held Senate seats that could prove pivotal to control of the chamber in this fall’s elections, one incumbent faces an evenly divided electorate while the Democrat holds a narrow edge in the other, according to new CNN polls conducted by SSRS.

In Wisconsin, the survey shows no clear leader, with 50% of likely voters behind Republican Sen. Ron Johnson and 49% backing his Democratic challenger, state Lt. Gov. Mandela Barnes.

In the race for retiring Republican Sen. Pat Toomey’s seat in Pennsylvania, Democratic state Lt. Gov. John Fetterman stands at 51% support to Republican candidate Mehmet Oz’s 45% support among likely voters, an advantage narrowly outside of the survey’s margin of error.