In South Carolina, where the Senate race is effectively tied, Graham is experiencing a similar problem with his own base: The Senate Judiciary Committee chairman trails Trump among likely Republican voters by 11 points, 81 percent to 92 percent. By comparison, Harrison has support from 90 percent of likely Democratic voters, roughly matching Biden’s 94 percent.

Polling in North Carolina, Michigan and Arizona reflected a similar trend, with Republicans nearly united behind the president but less certain about the down-ballot contests.

Senate Majority Leader Mitch McConnell (R-Ky.), who along with defending his 6-year Republican majority is looking to fend off a challenge from Democrat Amy McGrath, runs 7 points behind Trump in support from likely GOP voters, 84 percent to 91 percent.