Elon Musk is dramatically ratcheting up his effort to use his fortune to help Donald Trump win Pennsylvania — and inviting some new legal scrutiny along the way. Mr. Musk announced on Saturday night that he would give $1 million “randomly” once a day to a registered Pennsylvania voter who has signed a conservative petition put together by his super PAC. The sweepstakes is part of Mr. Musk’s push to register voters in the battleground state before a Monday deadline. Federal law says it is a...