Barack Obama sought to use his hat trick in the so-called Potomac Primary states here Tuesday to assert his position as the frontrunner for the Democratic presidential nomination, utilizing his victory speech to attack Republican John McCain on foreign policy and economic priorities. Obama, an Illinois senator, beat New York Sen. Hillary Clinton by 64 percent to 35% in Virginia, 60% to 36% in Maryland and an overwhelming 74% to 24% in Washington, DC (with almost all precincts reporting), bringing his winning streak to eight straight states. The race for delegates to the national nominating convention remains tight between the two, though Obama leads slightly, and before the Potomac contests Clinton had already turned her focus to winning the large states of Texas and Ohio on March 4 as a way to reassert herself. But while Obama took veiled shots at Clinton, he named only McCain in addressing the crowd of cheering supporters who heard him speak Tuesday night in Wisconsin, the site of one of next Tuesday's primaries. McCain, an Arizona senator, won all three Potomac primaries himself to further establish himself as the likely Republican presidential nominee. Though former Arkansas governor Mike Huckabee came close in Virginia, grabbing 41% of the vote to his rival's 50%, McCain still easily defeated his other main competitor and pulled ahead in the delegate race by a margin of 4-1. On Tuesday night, McCain received a highlight reel of the barbs he would face from Obama in a general election if he were to win the nomination. In his address, Obama attacked him for backing the war in Iraq to the detriment of the fight in Afghanistan and American domestic priorities. "John McCain won't be able to say that I ever supported this war in Iraq, because I opposed it from the beginning," he said, according to prepared remarks. "Instead of spending hundreds of billions of dollars in Baghdad, we could have put that money into our schools and hospitals, our roads and bridges - and that's what the American people need us to do right now." Without naming names, McCain returned the charge by criticizing the Democrats' foreign policy approach. "They will paint a picture of the world in which America's mistakes are a greater threat to our security than the malevolent intentions of an enemy that despises us and our ideals," he said in his prepared speech, "a world that can be made safer and more peaceful by placating our implacable foes and breaking faith with allies and the millions of people in this world for whom America, and the global progress of our ideals, has long been 'the last, best hope of Earth.'" Speaking in Texas Tuesday night, Clinton stressed that her years of experience made her the best person to handle the foreign and domestic challenges that would confront the next president. "I am a problem-solver. I believe that we need a president, starting on day one, who's going to roll up his or her sleeves and get to work," she said. "Waiting on that desk in the Oval Office are two wars - two wars - an economy in trouble, a health care system that is not taking care of people, an energy reliance on unstable regimes, and all of the problems that come from that." While Obama also attacked Republicans on Super Tuesday, when he split 22 national contests with Clinton, even those swipes were actually aimed at Clinton - to make the case why he, rather than she, could best stand against the GOP. And mentioning her directly, he drew major distinctions on policies connected to Iran and diplomatic engagement with unsavory regimes like the one running the Islamic Republic. "If I am your nominee," he said to loud cheers, "my opponent will not be able to say that I voted for the war in Iraq, because I didn't, or that I gave George Bush the benefit of the doubt on Iran, because I haven't, or that I support the Bush-Cheney doctrine of not talking to leaders we don't like, because I profoundly disagree with that approach." Clinton, unlike Obama, voted for a non-binding Senate resolution calling for Iran's Revolutionary Guard Corps to be labeled a terrorist group, which opponents labeled as giving Bush ammunition in going to war with Iran, and Clinton has couched her calls for dialogue with America's enemies with careful calculation of the goals and dimensions of such encounters. Obama's stances on these issues have caused some members of the more hawkish pro-Israel community concern regarding the candidate, but he has generally done well - if not quite as solidly as Clinton - with Jewish Democrats. Clinton, though, remained on top of the Jewish vote Tuesday, as exit polls reported on MSNBC gave her a 60-40 advantage with the demographic group. Information was not available from the Virginia and Washington races. The results made Jews one of the few constituencies that have retained their loyalty to Clinton, as she lost her strongholds of support among the groups she had counted on until now. Obama, for instance, won among Maryland women, according to the exit polls, as well as the Latino vote (55-44) in Virginia. The results - both the inroad Obama made among Clinton's traditional supporters, and the large margins of his victories - helped the Illinois senator make his case Tuesday that he's the Democrat on top.