Montana's turn to bask in the national political spotlight ends today when Democratic primary voters will pick between Hillary Clinton and Barack Obama in the most significant and fiercely contested presidential primary in state history.

With Obama and Clinton speaking in multiple Montana cities and on Indian reservations and mounting statewide campaigns, the presidential battle has overshadowed unusually humdrum primary races in both parties for other top-of-the-ticket offices.

Long shunned by major presidential candidates from both parties whose nominations were inevitably decided by the time Montanans finally cast their presidential ballots in early June, this year has been an aberration.

Montana's late presidential primary has attracted unprecedented interest this year from Clinton, Obama and their surrogates as they scrap for delegate and superdelegate votes in their prolonged fight for the Democratic nomination.

On the Republican side the names of John McCain, the presumptive nominee, and Ron Paul, will appear on the ballot Tuesday, but the results are meaningless. The state Republican Party held a Feb. 5 caucus of 1,600 party and elected officials, with former Massachusetts Gov. Mitt Romney winning the state's 25 delegate votes. He dropped out of the race shortly thereafter.

Democrats, meanwhile, have been downright enjoying their national role in the presidential race, highlighted by the appearance of both Obama and Clinton at a state party dinner in Butte on April 5.

"For Democrats in Montana, it's been wonderful," said state Democratic Chairman Dennis McDonald of Melville. "We've seen historic increases in registration. We've seen young people become involved in the process. Just a lot of folks who sometimes don't become involved in these primaries. Their interest has been rejuvenated. I think that's good for democracy and good for Montana in general."

A Lee Newspapers poll taken May 19-21 showed Obama leading Clinton, 52 percent to 35 percent, among likely Democratic primary voters, with 13 percent undecided. The margin of error was plus or minus four percentage points.

"I still think Obama has the advantage in Montana," said Craig Wilson, a political science professor at Montana State University-Billings, saying MSU-B's poll last fall found stronger support for Obama than for Clinton in the state.

He cited the Obama television advertising that's run most of May in Montana, while Clinton went up with an ad last week, and Obama's grassroots organization, which has been calling Montana households with some frequency.

"Both in Montana and maybe nationally, I think Obama has been out-organizing Clinton," Wilson said.

He predicted Montana Republicans will register their lowest ever percentage turnout in Tuesday's primary, while Democrats will see their highest.

Jim Lopach, a political science professor at the University of Montana, said he found the Lee poll results surprising and thinks Clinton will run better than the poll results showed.

"I thought Hillary Clinton would show more support," he said. "I thought given the state's history of political populism and the fact that successful Democratic candidates have won by attacking what we call 'the interests' and given the old union base in the Democratic Party, including teachers and government workers, I thought she would do better."

Obama has strong support among college students, but Lopach wondered if that will drop somewhat because college classes have ended. However, Obama had an early-voting effort organized among college students to get them to register and vote absentee early.

"One of the really surprising things of this campaign is the degree that Obama has out-organized Clinton as a newcomer," Lopach said.

At stake in Tuesday's Montana primary are 16 delegates pledged to Clinton or Obama, which will be allocated by a somewhat arcane formula, and one unpledged delegate.

Delegates are allotted in proportion to the vote given to Clinton, Obama and the "no preference" category that is also on the ballot. A candidate, including "no preference," needs at least 15 percent of the vote to win a delegate.

County Democratic conventions will be held throughout Montana on Thursday, with any registered voter pledging to be a Democrat eligible to participate. The vote in the 2004 election determines the number of delegates each county will select to the state Democratic Party convention in Helena June 8. Each delegate's voting weight is determined by the vote in the 2008 primary.

Delegates from the counties will meet in Helena to choose delegates to the party's national presidential nominating convention in Denver Aug. 25-28.

The former two eastern and western congressional districts each receive five national convention delegates, chosen by delegates from those regions. Then these 10 delegates, pledged to either Obama or Clinton or "no preference," will choose four more pledged at-large delegates, bring the total pledged delegates to 14.

Two more pledged party delegates will be nominated from the floor, allocated based on the statewide vote. Then an unpledged at-large delegate will be selected, bringing the total to 17 Democratic delegates from Montana.

Montana also has eight Democratic Party superdelegates, who can back whichever candidate they want for whatever reasons.

Three superdelegates have already endorsed Obama -- Ed Tinsley, the party's national committeeman from Helena, Jean Lemire Dahlman, national committeewoman from Forsyth, and former U.S. Sen. John Melcher, representing a national Democratic senior citizens' group.

The party's vice chairwoman, Rep. Margarett Campbell of Poplar, already backed Obama in April, but was forced to withdraw it because it was against party rules.

The remaining four superdelegates, including the top three Democratic state elected officials, have kept their powder dry, but are expected to announce their choices next week.

Gov. Brian Schweitzer, through spokeswoman Sarah Elliott, said he's excited to play a role in the process.

"We're waiting to see how the people vote and then we'll make our announcement," Schweitzer said through Elliott.

U.S. Sen. Jon Tester agreed it had been exciting to see Montanans play such an important role choosing between "two hard-working candidates."

"Their input will be a big factor in my superdelegate decision," Tester said. "But ultimately, I'm going to take a step back and ask, 'Who is the best candidate for Montana? Who's going to win in November?' It's common sense from there."

U.S. Sen. Max Baucus said it's been exciting to see Montana be in the national political spotlight for the first time in years.

"I'm going to wait until Montanans have their say on June 3," Baucus said. "Then I'll huddle with Brian and Jon to do what's right for Montana."

The remaining superdelegate is McDonald, the party chairman, who said, "Obviously, the vote in Montana on Tuesday will be a huge part of any decision that I will make."

The vote isn't the only factor, he said, adding: "I've maintained this campaign is so dynamic and has changed so much since the voting first started in January, I've always made some allowance for eventualities we don't already know, but that window is closing."

State Bureau Chief Chuck Johnson: 443-4920 or chuck.johnson@lee.net