More than half a dozen clashes between rallygoers and protesters interrupted President Donald Trump at an appearance in Clemson, S.C., on Wednesday night, where he had traveled to boost the campaign of Sen. Darline Graham.

It was not the first Trump rally in recent days marred by protests. But the drumbeat of outbursts, followed by angry reactions by the president and his supporters, showed the deep political divide in the country as the Nov. 3 elections draw near.

Trump is in the midst of a six-day barnstorm across some the country’s most conservative states, seeking to shore up support among his fans at a time when Republicans are increasingly pessimistic about whether they can retain control of Congress.

South Carolina is among a raft of traditionally Republican strongholds that have become battlegrounds this cycle.…