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Rick Santorum is charging into the Louisiana primary Saturday holding onto a healthy lead in the polls as he looks to shake off his latest losses to Mitt Romney.

The election will be critical for the former Pennsylvania senator who has done well in the Deep South, including wins in the Alabama and Mississippi primaries. But a victory in Louisiana appears crucial for him to close the gap in the delegate count before the party's nomination convention in Tampa in August.

Louisiana has 20 delegates up for grabs, but a candidate must win at least 25 percent of the vote to take at least some of them.

Romney now has 560 delegates, compared to 246 for Santorum, 141 for Gingrich and 66 for Paul in the race to reach 1,144 delegates and win the nomination outright.

On Saturday, Santorum and Gingrich attended the Pennsylvania Leadership Conference.

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Santorum told the crowd he didn't always understand conservatives' frustration with Washington but said he comprehends it now. He also said his 2006 reelection loss helped him grasp that frustration.

"In a sense, I didn't understand," he said.

Santorum also pointed to his consistent, social conservative stances to separate himself from the GOP presidential field, saying he offers an alternative to President Barack Obama.

He made the remarks before going to Milwaukee for the AFP Defending the Dream Conference. The state's primary in April 3.

Earlier this week, the candidates weighing in on some of the biggest issues in the country -- from the upcoming Supreme Court health care hearings to U.S. energy policy to the highly charged shooting death of a Florida teen.

Romney told Louisiana voters that Obama's health care law was an "unfolding disaster" and touted his plan to give Medicaid money to states and changes the tax code so that it encourages them to buy insurance.

The former Massachusetts governor made his remarks on the second anniversary of the president's plan.

"You'll note the White House is not celebrating ObamaCare today," Romney told a small crowd in Metairie, La., several miles west of New Orleans.

Still, conservatives are skeptical of Romney's stance on health care considering he signed a similar law as governor. His remarks also come four days before the Supreme Court is scheduled to hear on the constitutionality of the law, with those hoping to get a seat in the courtroom already standing in line outside the courthouse.

Romney enters the Louisiana primary after a solid, 12-percentage point victory Tuesday in Illinois over Santorum, hi closest rival.

He also has reached the 40-percent mark among voters, according to a Gallup poll released Friday. Romney led Santorum 40 percent to 26 percent among Republican voters nationwide in interviews conducted in the days surrounding the Illinois primary. This marks the first time a candidate has reached 40 percent during the primaries.

Gingrich finished third with 14 percent and Ron Paul received 8 percent, according to Gallup, which polled 1,157 Republicans and Republican-leaning independents.

Louisiana will be one of Romney's last chances to show he can win in the Deep South before the campaigns head north for roughly the next six weeks.

Among the key states remaining in the primary process through late June are Wisconsin, New York, Texas and California.

Santorum spent time Friday at a gun range in northern Louisiana and took back the comments he made a day earlier about Romney and Obama being so close on issues that Republicans might as well re-elect the president to a second term.

Santorum, emphatically said that he would support and vote for the Republican nominee, during a phone interview with Fox News.

"I've said it in every speech, if we don't give America a contrast we're not going to be successful. (But) the idea that I would vote for Obama over a Republican is outrageous," Santorum said. "This is why this is a joke and a creation of the Romney class."

Romney, who picked up a key endorsement this week from former GOP Florida Gov. Jeb Bush, on Friday also joined in the criticism of Obama's energy policy and for taking credit earlier this week for approving the southern leg of the Keystone XL oil pipeline, after his administration has not issued permits for the entire, 1,700-mile project from Canada to the Texas.

He said at a natural gas well in Shreveport, La., that the president's halt on oil drilling in the Gulf was a "huge mistake."