Mitt Romney and Rick Santorum are in a statistical dead heat in primary state Arizona, a poll indicated ahead of a GOP presidential hopefuls debate Wednesday. Thirty-six percent of likely Republican voters back the former Massachusetts governor while 32 percent support the former senator from Pennsylvania, a CNN/Time/ORC International poll released Tuesday indicated. The Friday-Monday telephone poll of 467 registered Republicans likely to vote in Tuesday\'s Arizona primary, has a margin of error of 4.5 percentage points. With the 4-percentage-point separation, the two candidates are in a statistical dead heat. Former U.S. House Speaker Newt Gingrich of Georgia ranks third in the poll, with 18 percent support, followed by Rep. Ron Paul, R-Texas, with 6 percent. Six percent are unsure and 2 percent preferred someone else or wanted none of the candidates, the poll indicated. The four major candidates are to face off for 2 hours in Mesa, Ariz., starting at 6 p.m. MST. CNN planned to televise the debate, the 20th of the primary season and the first since the candidates met in Jacksonville, Fla., Jan. 26. The debate was to be the last before the Arizona and Michigan primaries Feb. 28 and the 10-state Super Tuesday primaries March 6. Super Tuesday involves contests in Alaska, Georgia, Idaho, Massachusetts, North Dakota, Ohio, Oklahoma, Tennessee, Vermont and Virginia. Romney, who grew up in Michigan, is scrambling to stop Santorum from defeating him in his home state. Romney -- whose late father, George Romney, led former automaker American Motors Corp. from 1954 to 1962 before becoming Michigan governor from 1963 to 1969 -- has taken some criticism in Michigan for arguing against the auto industry\'s government bailouts, saying a managed bankruptcy would have been a better option. Romney, who has increasingly taken aim at Santorum, blasted his rival for seeking earmarks when he was a congressman and senator. Earmarks are local projects that lawmakers insert into spending bills. Santorum defended the earmarks, saying they helped Pennsylvania and were a legitimate part of his job. Romney made a comment about taxes and spending Tuesday that his campaign felt a need to clarify. \"If you just cut -- if all you\'re thinking about doing is cutting spending -- as you cut spending, you\'ll slow down the economy,\" Romney said Shelby Township, Mich., 25 miles north of Detroit, at a town hall-style meeting. \"So you have to, at the same time, create pro-growth tax policies,\" Romney said. His comment was pounced on by conservatives. \"It confirms yet again that Romney is not a limited-government conservative,\" Andy Roth, vice president for government affairs at the fiscally conservative Club for Growth, told MSNBC. Romney spokesman Ryan Williams later said, \"The governor\'s point was that simply slashing the budget, with no affirmative pro-growth policies, is insufficient to get the economy turned around.\" But Romney \"believes that budget cuts -- especially in the context of President [Barack] Obama\'s unprecedented spending explosion -- are a step in the right direction,\" Williams said. Romney plans to announce an economic plan in Detroit Friday that he said Tuesday would integrate his views on tax policy, spending and entitlement reform into a single package.