CHICAGO --Presumed Republican presidential nominee and Ariz. Sen. John McCain is raising money in the back yard of Democratic presidential hopeful Barack Obama. "I will campaign here. I will campaign hard. And I believe that we can be very competitive here," said McCain. One of key issues that McCain is raising in Chicago and as he campaigns around the country is wasteful government spending. And earlier in the day, he lamented Thursday's overwhelming defeat of an amendment to eliminate so-called "earmarks" next year, the secretive pork barrel spending that most congressmen revel in. "Anyone who had the misfortune of watching it will know how hard it is trying to do the lord's work in the city of Satan," McCain said. McCain's also firing back at a fellow senator and possible Democratic opponent Barack Obama, who said Thursday that McCain flip-flopped on the Bush tax cuts from an opponent to a supporter to win the GOP nomination. "He made a decision to reverse himself on that, but he was right then and he's wrong now," Obama said. "I can assure you that I didn't flip-flop, but more importantly he wants to raise taxes. He wants to raise people's taxes on, quote, the rich. A lot of people are astonished to find out they fall into that category," McCain said. The other key issue this fall, according to McCain, is national security, which has always been his strong suit as a former Navy officer and POW in Vietnam. But earlier this week, ten former generals and admirals endorsed Obama on the grounds of judgment and temperament. "No shock Barack kind of guy, no drama Obama," said Gen. Tony McPeak (Ret.), Obama supporter. "I will be glad to put my qualifications and experience and background and judgment in comparison to Senator Obama, but I'm sure he is honored by the support of those Americans who served our nation so honorably in uniform," said McCain. Friday is the 35th anniversary of McCain's release from a POW camp in Hanoi during the Vietnam War after his fighter jet was shot down in those waters.