With recession in the air and gasoline over $4 a gallon, presumptive presidential nominees John McCain and Barack Obama focused on the economy today, each accusing the other of not understanding how it works.Obama launched his "Change That Works for You" tour in Raleigh, N.C., as spokesman Bill Burton sought to whittle away at McCain's credentials as a fiscal conservative, arguing that "he has no problem spending hundreds of millions of dollars on tax breaks for big corporations and a permanent occupation of Iraq - policies that have left our children with more debt than any Administration in history."The McCain campaign fired back that Obama's economic solutions would "further weaken our economy.""While hardworking families are hurting and employers are vulnerable, Barack Obama has promised higher income taxes, Social Security taxes, capital gains taxes, dividend taxes, and tax hikes on job creating businesses," campaign spokesman Tucker Bounds said.The Rasmussen poll also affirmed that the economy is the top political issue five months ahead of election day, with half of the poll respondents saying that to buy groceries they have had to curtail spending in other areas.