By THOMAS BEAUMONT, Associated Press In the first major flex of his influence since Donald Trump was elected, Elon Musk brought to a sudden halt a bipartisan budget proposal by posting constantly on his X megaphone and threatening Republicans with primary challenges. The social media warnings from the world’s wealthiest man preceded Trump’s condemnation of a measure negotiated by GOP House Speaker Mike Johnson, which effectively killed the stopgap measure that was designed to prevent a partial shutdown of the federal government. Washington was scrambled a day after Musk’s public pressure campaign.