Even the most competitive and evenly balanced states are infected by the same contagion as the hardened one-party states.

The North Carolina Republican had already made up his mind to leave the Senate, but the run-in with the president over Medicaid moved up the timeline of the announcement.

Republican Sen. Thom Tillis of North Carolina says he won't seek reelection. That news Sunday comes one day after he announced his opposition to President Donald Trump’s tax breaks and spending cuts package because of its reductions to health care programs.