WASHINGTON — U.S. President Donald Trump boasted Tuesday of a "turnaround for the ages" in a State of the Union speech, seeking to reverse his dismal polls and see off mounting challenges at home and abroad ahead of crucial midterm elections. Arriving to address a joint session of Congress, Trump was welcomed with cheers and a standing ovation from Republicans — while Democrats remained seated in protest. "My fellow Americans, our nation is back bigger, better, richer and stronger than ever before," Trump said. The 79-year-old hoped the primetime stage will help him to sell voters on the achievements of a breakneck and deeply divisive first year back in power. Trump is deep underwater in opinion polls and Republicans fear they could lose their tiny majority in the House to the Democrats — paralyzing the rest of Trump's second term and exposing him to a possible third impeachment. The Republican however struck a defiant tone in the first official State of the Union of his second term. "Tonight, after just one year, I can say with dignity and pride that we have achieved a transformatio