Voters will head to the polls in six states today, but one state - Wisconsin - reigns supreme in garnering national attention. The Badger State holds its highly anticipated recall election in which embattled Republican Gov. Scott Walker faces  off against Milwaukee Mayor Tom Barrett.

In addition to the recall election, five states - California, South Dakota, New Jersey, New Mexico and Montana -  hold state and presidential primaries.

Here are the five things to watch when the polls close this evening.

1. Wisconsin Recall

Arguably the biggest event on the political calendar between now and November, Wisconsin's election to recall Gov. Scott Walker has been a hard-fought and expensive race.  More than $60 million has been spent before Tuesday's recall vote, which many view as a barometer of what might happen in the general election.

The election has been more than  a year in the making, with the groundwork laid in the winter of 2011, when Walker, 44, proposed and passed legislation limiting collective bargaining rights for many public sector employees, infuriating labor unions across Wisconsin and the country.

Turnout is expected to be high. The state's Government Accountability Board, which oversees statewide elections, predicts a 60 to 65 percent turnout among the voting-age population - an increase from the 2010 election when Walker and Barrett faced off the first time for governor. Roughly 50 percent of the voting-age population turned out for  that race.

Polls show Walker in the lead over Barrett, but it's close. Both parties maintain that it all comes down to turnout.

2. Wisconsin State Senate

In addition to the governorship, Democrats are hoping to flip control of Wisconsin's state Senate on Tuesday.

Walker is not the only incumbent on the ballot. Four Republican state senators also face recall,  plus Walker's Lt.. Gov.  Rebecca Kleefisch. Wisconsin's 33 member  Senate is evenly split, with 16 representatives from both parties and one vacancy. The results of Tuesday's election will likely flip control to one party. Several Wisconsin state senators have already faced recall elections, and two Republicans have lost their seats.

3. California's Big Congressional Change

A redistricted congressional map is expected to yield a sizable change in the California's 53- member congressional delegation. For the first time in the state's history, the Bear Republic's map was drawn not by the legislature but by a nonpartisan, redistricting commission. The result is a map that looks very different from the one preceding it. Six members are retiring - four Republicans and two Democrats.

The congressional primaries are "top two" primaries. The top two finishers on the ballot will face off in the general election, regardless of their party affiliation, which means that heavily Democratic districts will likely see Democrat vs. Democrat in November, and vice-versa for traditionally Republican districts.

4. Obama vs. Clinton in New Jersey House Race

Reps. Bill Pascrell and Steve Rothman, once allies,  are fighting each other for their political lives in New Jersey's new 9th Congressional District, after redistricting eliminated Rothman's former district.

Rothman endorsed Obama in 2008, and while Obama has not publicly endorsed Rothman, he did meet with him privately at  the White House last week.

Pascrell endorsed Hillary Clinton, and this cycle Bill Clinton has returned the favor, endorsing Pascrell and campaigning on his behalf.

A handful of congressional districts in California see will intraparty battles between current House members, but because of the state's top-two finishers system, it's likely that those battles will not be decided until November.

5.  Cigarette Tax Proposal

California is associated in the cultural zeitgeist as a land of healthy living, but the state hasn't raised its cigarette tax in more than a decade. That could change  Tuesday  as voters  cast ballots on Proposition 29, a statewide initiative to add a $1 a pack tax to cigarettes, the proceeds of which would go to  fund cancer research.

The referendum has drawn a great deal of attention in the state - $47 million has been spent in advertisements. Some of the major criticism of the referendum has been aimed at the ultimate source for the proceeds. California faces a multi-billion dollar deficit, and opponents of the law have questioned the logic behind adding a new tax that would ultimately go to funding research as opposed to closing some of that deficit.

Polling shows a narrow majority of support for the measure, but the outcome is anyone's guess.