New York | Elon Musk is dramatically ratcheting up his effort to use his fortune to help Donald Trump win the critical state of Pennsylvania – and inviting some new legal scrutiny along the way.

Mr Musk announced he would give $US1 million ($1.5 million) “randomly” once a day to a registered Pennsylvania voter who has signed a conservative petition backing free speech and the right to bear arms, put together by his super political action committee (PAC).