(Bloomberg) -- Republican frontrunner Donald Trump said he would block Nippon Steel Corp.’s deal to buy United States Steel Corp. if he wins the November election, highlighting how the former president’s economic nationalism could imperil foreign investment in the US. Most Read from BloombergMusk’s $55 Billion Pay Package Voided, Threatening World’s Biggest FortuneTrump Risks Losing More Than Half of Swing-State Voters If Found GuiltyByron Allen’s Latest Takeover Bid: Paramount for $14 BillionS&