(AP) - John McCain accused Barack Obama ofcompiling "the most liberal voting record in the United StatesSenate" Friday night in their first debate of a close campaign forthe White House. The Democrat shot back, "Mostly that's just meopposing George Bush's wrong-headed policies."

Obama said his Republican rival has been a loyal supporter ofthe unpopular president across the past eight years, adding thatthe current economic crisis is "a final verdict on eight years offailed economic policies promoted by President Bush and supportedby Sen. McCain."

The two men clashed over spending, taxes, energy and - at length- the war in Iraq during their 90-minute debate.

McCain accused his younger rival of an "incredible thing ofvoting to cut off funds for troops in Iraq and Afghanistan," areference to legislation that cleared the Senate more than a yearago.

Obama disputed that, saying he had opposed funding in a billthat presented a "blank check" to the Pentagon while McCain hadopposed money in legislation that included a timetable for troopwithdrawal.

Obama opposed the invasion of Iraq in 2002, before he was amember of Congress, while voted to authorize the war as a member ofthe Senate.

"You were wrong" on Iraq, Obama repeated three times insuccession. "John, you like to pretend the war began in 2007."

McCain replied that Obama has refused to acknowledge the successof the troop buildup in Iraq that McCain recommended and Bushannounced more than a year ago.

The two presidential candidates stood behind identical woodenlecterns on stage at the performing arts center at the Universityof Mississippi for the first of three scheduled debates with lessthan six weeks remaining until Election Day. The two vicepresidential candidates will meet next week for their only debate.

The 47-year-old Obama is seeking to become the nation's firstblack president. McCain, 72, is hoping to become the oldestfirst-term chief executive in history - and he made a few jokes athis own expense.

"I've been around a while," he said at one point. "Were youafraid I couldn't hear you?" he said at another after Obamarepeated a comment.

It was a debate that almost didn't happen. McCain decided at thelast minute to attend, two days after announcing he would try tohave the event rescheduled if Congress had not reached an agreementon an economic bailout to deal with the crisis now gripping WallStreet.

The two men were pointed but polite as they covered most issues,although at least once, McCain sought to depict his rival as naiveon foreign policy. That was particularly true when it came toObama's statement that it might become necessary to send U.S.troops across the Pakistani border to pursue terrorists.

"You don't say that out loud," retorted McCain. "If you haveto do things, you do things."

McCain also seemed eager to demonstrate his knowledge of foreignpolicy, recalling the names of three former leaders of the SovietUnion in one sentence.

Moderator Jim Lehrer's opening question concerned the economiccrisis gripping Wall Street. While neither man committed tosupporting bailout legislation taking shape in Congress, theyreadily agreed lawmakers must take action to prevent millions ofAmericans from losing their jobs and their homes.

Both also said they were pleased that lawmakers in both partieswere negotiating on a compromise.

McCain made a point of declaring his independence from Bush. "I have opposed the president on spending, on climate change,on torture of prisoners, on Guantanamo Bay, on a long - on the waythat the Iraq War was conducted. I have a long record and theAmerican people know me very well ... a maverick of the Senate."

He jabbed at Obama, who he said has requested millions ofdollars in pork barrel spending, including some after he beganrunning for president.

As he does frequently while campaigning, the Republican vowed toveto any lawmaker's pork barrel project that reaches his desk inthe White House. "You will know their names and I will make themfamous," he said.

The stakes were high as the two rivals walked on stage. Thepolls gave Obama a modest lead and indicated he was viewed morefavorably than his rival when it came to dealing with the economy.But the same surveys show McCain favored by far on foreign policy.

Both candidates had rehearsed extensively, Obama prepping withadvisers at a resort in Clearwater, Fla., and McCain putting indebate work at his home outside Washington.

The two presidential hopefuls are scheduled to debate twicemore, at Belmont University in Nashville on Oct. 7 and at HofstraUniversity in Hempsted, N.Y., on Oct. 15. Vice presidentialcontenders Sarah Palin and Joe Biden are to square off in a singledebate Oct. 2 at Washington University in St. Louis.