(CNN) -- Wisconsin and Hawaii become the latest battlegrounds in the struggle for the Democratic presidential nominee Tuesday, while Republican Sen. John McCain is looking for victories to finally knock his last remaining major rival out of the race.
Winter weather over the weekend hampered the candidates' efforts to campaign in Wisconsin.
In the Democratic presidential race, Sen. Barack Obama is looking to increase his lead over Sen. Hillary Clinton in the race for delegates with wins in the Wisconsin primary, one of the nation's oldest, and the Hawaii Democratic caucuses, the state were the Illinois senator was born and where he still has family.
Obama was able to stake a claim on the front-runner position after winning eight contests in a row, including the Potomac primaries in Maryland, Virginia and the District of Columbia last week.
Obama leads Clinton, a senator from New York, in the overall delegate count -- 1,262 to 1,213, according to CNN estimates. The estimate includes the support of superdelegates, the party officials and elected officials who are free to vote for any candidate at the party's national convention.
Both candidates are short of the 2,025 delegates needed to win the nomination, and it is very likely the roughly 800 superdelegates will ultimately decide who will be crowned the Democrat's presidential nominee.
Recent polls show Clinton has a chance in Wisconsin at ending Obama's winning streak. According to an American Research Group poll conducted February 15 and 16, the two candidates are in a statistical tie, with Clinton at 49 percent and Obama at 43 percent. The poll's margin of error is plus-or-minus 4 percentage points. Watch the candidate stump in snowy Wisconsin »
Another poll of Wisconsin Democratic primary voters conducted by Research 2000 for Madison television station WISC also indicates the race is too close to call. The WISC poll had Obama at 47 percent and Clinton at 42 percent. The poll's margin of error is plus-or-minus 5 percentage points.
In Wisconsin, Clinton is expected to do well in the Milwaukee metropolitan area and the the industrialized Fox River valley, which includes Appleton and Green Bay, in the northeastern portion of the state. Both areas have a high percentage of blue collar voters, a group Clinton has done well with in previous primaries.
In a campaign stop in the Green Bay-area town of De Pere, Wisconsin, Clinton continued to hit on economic issues. Watch Clinton talk about her economic blueprint »
"The economy is not working, " she said. "What we really need in America is an economy that's producing good jobs with rising wages for everybody willing to work hard. I've been focused on the economy throughout the campaign."
Obama is expected to do well in the state's capital, Madison, which is known for its progressive politics. Obama, who has outperformed Clinton among younger voters, should also do well in the Madison area because of the large student body at the University of Wisconsin.
In the week leading up to Tuesday's primaries, Obama spent much of his time campaigning in Wisconsin, while Clinton split her time between Wisconsin, Texas and Ohio. Texas and Ohio hold primaries March 4, and even Clinton's own supporters suggest she must do well in those two delegate-rich states to keep Obama from winning the nomination.
While on the campaign trail last week, Clinton questioned whether Obama could deliver on his rhetoric, saying "I am in the solutions business. My opponent is in the promises business."
While campaigning in Youngstown, Ohio, Monday, Obama responded to Clinton's criticism. Watch Obama fire up supporters in Ohio »
"Speeches don't put food on the table, but the only way that we're going to bring about change is if all of you get excited about change, because that's the only way that we're going to take on the special interests," he said.
No polling is available for the Hawaii Democratic caucus. The Clinton campaign dispatched Chelsea Clinton, the candidate's daughter, to rally support. Obama's sister, Maya Soetoro-Ng, has stumped for her brother. Watch the Democrats battle for Hawaii »
Washington State Democrats are also heading to the polls Tuesday to vote in that state's primary, but the results will have no impact on how the Washington state delegates will be distributed. The delegate allocation was determined February 9 when Washington state Democrats held caucuses. Obama won those handily over Clinton, 68 percent to 31 percent.
McCain, the presumptive Republican nominee, is looking for big wins in the Wisconsin and Washington state primaries to demonstrate he is starting to unify the Republican party behind his nomination, including conservatives upset by his positions on immigration, campaign finance and other issues.
In a further sign the GOP establishment was starting to rally around him, former President Bush endorsed McCain Monday during an event in Houston, Texas. Watch George H. W. Bush endorse McCain »
"In conversations I had with President Bush, he made it very clear that we, as a party, must unite and move forward and attract not only our members of our own party, but independents and the so-called Reagan Democrats," McCain said.
McCain has won 830 delegates in the previous Republican contests. Last week, McCain won the endorsement of former GOP presidential candidate Mitt Romney, who asked his delegates to vote for McCain at the national convention. There is no requirement, however, that Romney's delegates follow his wishes.
If the 286 delegates pledged to Romney vote for McCain, the Arizona Republican would be close to the 1,191 delegates needed to win the nomination outright.
McCain also hopes he can score big enough wins to convince Mike Huckabee, the last remaining top-tier Republican candidate challenging McCain, to drop out of the race. The former Arkansas governor has vowed to stay in the race until McCain has enough delegates to win the nomination, saying voters deserve a choice. Watch Huckabee discuss his longshot campaign »
"I'd like to think we've got enough support in Wisconsin, that we can actually win here, and it would be a very big thing for us," Huckabee said during a campaign stop in Hudson, Wisconsin, Monday. "But it would also be a good thing for Wisconsin for me to win, because it would show that the party was wrong to say this is over, and it would also be wrong to end the game before people in places like Wisconsin had a chance to vote."
Recent polls suggest the Republican race in Wisconsin is closer than McCain would like. The American Research Group poll conducted February 15-16 has McCain and Huckabee in a statistical tie, with McCain with 46 percent and Huckabee at 42 percent. The poll's margin of error was plus-or-minus 4 percentage points.
The WISC poll conducted February 13-14, however, gave McCain a clear lead over Huckabee, 48 percent to 32 percent. The poll's margin of error was plus-or-minus 5 percentage points.
No recent poling is available for the Washington Republican primary, which the state party uses to allocate nearly half of the state's delegates. The other half of the state's delegates were allocated according to the results of caucuses held February 9.
McCain won a plurality of the caucus vote with 26 percent. Huckabee came in second with 24 percent and Texas Rep. Ron Paul came in third with 22 percent. E-mail to a friend