WASHINGTON (AP) - July 31, 2012 --Mitt Romney is heading home.A spokesman says the Republican presidential candidate's plane has left Poland and is headed for Boston. Romney concluded a seven-day overseas tour on Tuesday after a speech in Poland. His earlier stops were in England and Israel. The three-nation trip was Romney's first as the presumptive Republican presidential nominee. He struggled through a series of missteps and at times drew sharp criticism from British and Palestinian officials. Speculation is already turning toward Romney's choice of a running mate. His campaign released a statement Tuesday suggesting the announcement would come soon.