VINEYARD HAVEN, Mass. — President Barack Obama said Saturday the end of combat operations in Iraq doesn't just reaffirm the country's sovereignty, but also makes good on one of his principle campaign pledges. Obama used his weekly radio and Internet address to highlight Tuesday's formal end to U.S. combat missions in Iraq — the realization of a promise he made as a candidate in the 2008 election. Remaining troops will assume a backup and training role, a shift Obama will underscore with a visit to Fort Bliss, Texas, and an Oval Office address to the nation on Aug. 31, the date he targeted last year for the change in focus. U.S. troop strength dropped below 50,000 this week, a milestone also highlighted by the administration. Driving home his point, the president said, "The bottom line is this: The war is ending. Like any sovereign, independent nation, Iraq is free to chart its own course. And by the end of next year, all of our troops will be home." Senate Republican leader Mitch McConnell of Kentucky said while "much hard work remains" in Iraq, "U.S. combat forces in Iraq have done everything their country asked of them over the past seven years. We owe them our deepest gratitude for all they have done, are doing, and will continue to do in defense of our nation." Yet, the end to U.S. combat action in Iraq falls short of the "mission accomplished" moment that bedeviled former President George W. Bush, given the continuing violence and political instability in Iraq and the ongoing commitment of remaining U.S. troops. But Obama seized on it as an opportunity to show he's making good on a promise that was a driving force for his presidential campaign, before his term in the White House was overtaken by economic issues. Obama also pledged continued support for veterans and the Veterans Affairs Department, noting that the Iraq and Afghanistan wars produce different injuries than past conflicts.