BRIARCLIFF MANOR, N.Y. — Donald Trump ended one of his toughest days of the campaign by doing something he rarely does: reading a prime-time speech from a teleprompter.

The 17-minute address, delivered Tuesday to supporters at the Trump National Golf Club Westchester, was designed to reassure the Republican Party with a promise to fight special interests and deliver a major broadside attack on Hillary Clinton next week.

“I understand the responsibility of carrying the mantle,” Trump said on a night he was expected to win California and four other Republican primaries. “And I will never, ever let you down.”

The party was in full panic Tuesday over how to deal with a candidate who appeared uninterested in the advice of party leaders and some in his own campaign. “I will make you proud of our party and our movement,” Trump said.

Trump only alluded to some of the controversy he has engendered in recent days by attacking a federal judge of Mexican descent, and the questions that have arisen within his party about his temperament. “Some people say I’m too much of a fighter,” Trump said. “My preference is always peace, however.”

Trump tried to turn his combative reputation into a positive, pledging to fight against special interests and a rigged system and in favor of American values.

Trump also reached out to Bernie Sanders supporters in hopes they will abandon Democrats once Hillary Clinton secures the nomination.