By John Whitesides, Political Correspondent
WAUSAU, Wis (Reuters) - Barack Obama hit back at rivalHillary Clinton on Saturday before a Wisconsin showdown nextTuesday in their Democratic presidential battle, as Clintonheaded to the state for the first time.
Obama, a first-term Illinois senator, has beaten Clinton inthe last eight state contests to gain the upper hand in theirduel to become the Democratic presidential nominee inNovember's election.
Obama has spent four days in Wisconsin since his last roundof victories last Tuesday, while Clinton has focused on March 4votes in Ohio and Texas hoping victories there will rejuvenateher flagging campaign.
He launched another advertisement on Saturday responding toClinton's recent attacks. The New York senator has criticizedhim as more talk than action, and aired two ads in Wisconsinthis week attacking his refusal to debate in the state and hishealth care and retirement plans.
"After 18 debates, with two more coming, Hillary saysBarack Obama is ducking debates? It's the same old politics,"an announcer says in Obama's new ad.
"Obama has a plan to protect Social Security benefits andthe current retirement age. Hillary doesn't," the spot said.
Obama and Clinton were to appear separately on Saturdayevening at a party dinner in Milwaukee. Clinton will campaignin the state on Sunday and Monday before the primary.
Democrats in Hawaii also vote on Tuesday but Obama, who wasborn in the state, is expected to win there.
Clinton, under pressure to slow Obama's momentum, hasemphasized her economic message in an appeal to middle- andlower-income voters.
"It is time we had a president who was a fighter, a doerand a champion for the American middle class," Clinton said onFriday during an economic round-table in Cincinnati, Ohio.
"This primary election offers a very big choice to thevoters of Ohio," she said. "You can choose speeches orsolutions."
CLINTON TRAILING IN POLLS
Clinton's criticism came as a poll showed her trailingObama in Texas by 6 percentage points. The American ResearchGroup survey, which had a margin of error of 4 percentagepoints, showed Clinton with 42 percent support versus 48percent for Obama.
Texas and Ohio are "must win" states for Clinton, who islagging Obama in the race for pledged delegates awarded by thestate-by-state contests to pick a Democratic nominee. Thedelegates will choose the Democratic candidate at a nominatingconvention this summer.
Obama also has focused on economics in Wisconsin. OnSaturday, he visited a community college to tout proposals fora tax credit to make community and technical colleges moreaffordable.
"We are at a moment where people are finding it harder andharder to get ahead," he said, adding his plan would "put alittle wind at the backs" of average Americans.
A recent poll showed Obama with a 5-point lead in Wisconsinover Clinton.
Republican front-runner John McCain took the day off onSaturday before winning the endorsement of former PresidentGeorge H.W. Bush, the father of the current president, at anevent in Houston on Monday.
McCain is almost certain to be the Republican presidentialnominee for the November general election after defeating hismain rival, former Massachusetts Gov. Mitt Romney, and winninghis endorsement. McCain's nearest rival is former Arkansas Gov.Mike Huckabee, who is running a distant second.
(Additional reporting by Caren Bohan and Jim Wolf; Editingby Alan Elsner)
(To read more about the U.S. political campaign, visitReuters "Tales from the Trail: 2008" online athttp://blogs.reuters.com/trail08/
