PHOENIX — Arizona is in the thick of things on Super Tuesday, with a home-state candidate who’s making national waves on one party’s ballot and a fiercely contested battle on the other’s. And because of the way the races are playing out, the state won’t be as easily overlooked as it has been in the past.

Arizona Republicans go to the polls Tuesday in their winner-take-all contest, with favorite-son Sen. John McCain leading in recent polls and enjoying the backing of a broad swath of the party bigwigs.

On the Democratic side, Hillary Rodham Clinton and Barack Obama are in a two-way battle for every delegate they can get in the more than 20 states holding primaries and caucuses Tuesday.

Arizona is small compared with such big states as California and New Jersey also voting Tuesday but the tightness of the Democratic race and the primary’s relatively early date help counterbalance that, experts say.

Arizona is in the mid-range among the Super Tuesday states in number of delegates at stake, with 53 at stake on the Republican side and 56 for Democrats.

“It’s important this year, particularly because it’s not a blowout on either side,” said Margaret Kenski, a Republican pollster from Tucson.

“If you have a situation where there’s a clear front-runner, then a small state like ours doesn’t make much difference,” Kenski said. “But in a situation like this which is very close, then everything is important. The delegate counts are closer than I’ve seen them.”

Referring to the Democrats, University of Arizona political science professor William Dixon said: “It certainly has a role to play because the candidates can pull delegates out of Arizona.”

Only registered Democrats and Republicans can vote in their respective party’s primary. Unlike the September state primary election, independents can’t participate Tuesday. Polls are open from 6 a.m. to 7 p.m.

The most recent public poll showed McCain leading Mitt Romney on the Republican side.

Meanwhile, the Democratic race in Arizona was seen as close, an appraisal apparently shared by the Democratic contenders’ strategists too.

Though their time and money is spread thin with coast-to-coast geography to cover, Clinton and Obama each visited the state in the past two weeks. Clinton also sent her husband, former President Bill Clinton, and Clinton herself returned to Tucson Saturday.

McCain is coming off a slim but still significant win over Mitt Romney in Florida last Tuesday. McCain has netted big endorsements since then, and he hopes Super Tuesday will put him over the top.

Romney’s strategy in the final days before Feb. 5 reportedly targets states with heavy concentrations of Romney’s fellow Mormons, but the candidate will not visit Arizona even though it fits the bill, his campaign said Saturday. Instead, it will rely on a local organization built up in the past year.

“There’s going to be a strong Romney presence in Arizona, don’t get me wrong,” Romney spokeswoman Gail Gitcho said. “We’re relying on that extraordinarily strong grass roots effort here.”

McCain’s Arizona partisans expressed confidence.

“He’s going to win,” said Mike Hellon, a longtime Republican Party activist who is McCain’s Southern Arizona coordinator. “The numbers look really good for him.”

Though a slice of GOP conservatives regard McCain as too willing to find common ground with Democrats on issues ranging from campaign finance to immigration, it would be a major upset — and an embarrassment — if McCain were to lose his home state.

“From outside Arizona, it would be like what do those people know about him that we don’t,” Dixon said.

However, said Dixon, “the competitive race is clearly going to be on the Democratic side.”

While the Republican contest gives the winner all the party’s delegates, Democratic delegates will be awarded proportionally to results both statewide and in the eight congressional districts. That means both Clinton and Obama have a reason to run hard, at least in selected areas of the state.

“Because it is such a close race right now, every state is going to be important to the candidates,” said state Rep. David Lujan, a Phoenix Democrat and an Obama supporter. “The candidates are not necessarily going state by state, they’re going congressional district by congressional district, trying to pick up delegates.”

Obama’s campaign got a boost when Democratic Gov. Janet Napolitano endorsed him on Jan. 11, prompting an uptick in calls from new supporters, said Raul Avillar, Obama’s state director for Arizona. “It meant a lot to us.”

Napolitano last year had used her unilateral authority under state law to change the primary date, moving it up to Feb. 5 from the default date of Feb. 26.

She said she hoped it would give Arizona a more important role in the nominating process.

That was after Arizona Democrats tried but failed to snag a party-sanctioned early Western contest that instead was awarded to Nevada.