Tesla and Twitter CEO Elon Musk visited with House Speaker Kevin McCarthy (R., Calif.) in his Capitol Hill office Thursday evening. Mr. McCarthy told reporters that Mr. Musk had come to wish him a happy birthday. "We've been friends for years," he said. Mr. Musk endorsed Mr. McCarthy for speaker and has donated more money to Mr. McCarthy's campaign and political committees in the past two decades than to any other member of Congress. Meanwhile, conservatives have cheered the changes Mr. Musk has made to Twitter. Mr. McCarthy turned 58 on Thursday.