Senators delivered a show of confidence in Jerome Powell, President Trump’s pick for chairman of the Federal Reserve System, voting overwhelmingly Tuesday to confirm him to the position. Mr. Powell, who’s been part of the Fed’s board of governors, will replace Janet Yellen, whom Mr. Trump declined to nominate for a second term. As chairman, Mr. Powell will be the most important voice in deciding how the Federal Reserve moves forward with the economy appearing to be humming yet again, even as banks chafe against restrictions imposed in the wake of the 2008 Wall Street collapse. Tuesday’s 85-12 vote saw just four Republicans and eight members of the Democratic Caucus vote against Mr. Powell, who had enjoyed bipartisan support before. “He has served as a steady voice and thoughtful leader,” Majority Leader Mitch McConnell said in urging his confirmation. The U.S. Chamber of Commerce called Mr. Powell the “right man at the right time.” The Federal Reserve is an independent government agency charged with keeping inflation in check and supporting job growth. It took on an outsized role in the Wall Street collapse, sparking criticism from some quarters that it had overstepped. More recently the Fed has raised some key interest rates, hoping to keep the economy growing without overheating. Mr. Trump had criticized Ms. Yellen’s performance during the presidential campaign, but in office he changed his tone, even calling her tenure “excellent.” But he did not give her a second term, making her the first chair in decades to be ousted after one four-year period. Her predecessor, Ben Bernanke, served for two terms, and before that Alan Greenspan served for nearly two decades.