President Donald Trump will face an important obstacle — from within his own party — as he seeks to replace Federal Reserve Chair Jerome Powell. Sen. Thom Tillis, R-N.C., said Sunday he will block any Trump appointees to the central bank, including for the new chair, in light of revelations over the weekend that the Justice Department is investigating Powell for potential perjury charges. “If there were any remaining doubt whether advisers within the Trump Administration are actively pushing to end the independence of the Federal Reserve, there should now be none. It is now the independence and credibility of...