"[Alaska Sen. Lisa Murkowski] has voted with the Democrats more than any Republican up for reelection this year." - Sarah Palin in robo calls going out to Republican voters across Alaska in support of Murkowski challenger Joe Miller in today's primary.

It's all grudge matches today as primary voters head to the polls today in Florida, Arizona, Vermont and Alaska. While Vermont's races are as neighborly as a raw milk diary commune, the other three states have seen some of the wildest campaigns and spending of the year.

Alaska has the surprise race of the day. There, it's Sarah Palin versus her old intra-party foe, Sen. Lisa Murkowski. Palin defeated Murkowski's father, Frank, in the 2006 gubernatorial primary with a flurry of corruption charges flying against him. Palin is backing Joe Miller and campaigning hard for him. Unlike some of her other long-shot endorsees, like Clint Didier in Washington, Palin has not let up down the stretch. And though it's hard to find reliable polling on Alaska, surveys suggest that Murkowski's lead was larger than 20 points in July - a wide lead, but perhaps not wide enough for a candidate who likely has spent more than $1 million on a race against an opponent who has spent less than a quarter of that.

Miller has an impressive resume. He's a West Point graduate who commanded combat troops in the first Gulf war. Miller got a law degree from Yale and, after a brief career in private practice, served as a state judge and a federal magistrate. Like Ken Buck in Colorado, he has Tea Party clout but mainstream credentials. But without Palin's help, which began with a June fundraiser by husband Todd and has escalated since, Miller wouldn't be in the game.

Murkowski has a two-generation-old campaign organization and oil barrels full of money plus lots of name identification. Plus, Palin's popularity in the state took a knock when she resigned as governor. But in a low-turnout affair, Miller might still have an, ahem, outside shot.

Florida has two big races - the contest between Democrats Kendrick Meek and Jeff Greene for the party's Senate nomination and the Republican fight for the gubernatorial nod between Bill McCollum and Rick Scott.

Greene, a billionaire real estate speculator, imploded late in the campaign amid allegations of unpleasant behavior both personal and professional. Meek, boosted by visits from the 42nd and 44th presidents, has soared in the polls and seems likely to hold on to win his spot in a three-way race with sure-to-be Republican nominee Marco Rubio and Independent Gov. Charlie Crist.

The polls in McCollum and Scott's race have not been so easy to read. While McCollum has bashed Scott for the Medicare fraud allegations at his current and former health care companies, it hasn't been a Greene-like meltdown. McCollum, the state's attorney general, helped his cause by proposing a "tougher than Arizona" immigration law for the state. While most pollsters have seen the race running to McCollum's favor, Democratic survey group Public Policy Polling shows a late surge for Scott. Complicating the subject - early voting is very popular in Florida and voters have been filling out ballots for two weeks already. Does that mitigate a McCollum rally or a Scott surge?

The big number to watch will be voter turnout. A Republican strategist tells Fox News to expect a 70 percent increase over 2006 primary turnout on the GOP side with 1.7 million votes cast. If Republicans outvote Democrats by a wide margin with hot races on both sides, count that an ill omen for Dems this fall.

Arizona's marquee contest in between Sen. John McCain and challenger J.D. Hayworth. It was once was billed as the Tea Party challenge of the year and endlessly touted by a hoard of news outlets as prima facie evidence of hew the Tea Party was destroying the Republican Party. But Hayworth's bid seems to have fizzled. It's hard to tell what did more damage - McCain spending $21 million to lock up all the airwaves or the embarrassing infomercial that surfaced on YouTube showing Hayworth hawking a system to get "free money" from the government. While the stories today muse on McCain's conservative turn on immigration and other issues during the primary, count one of the big narratives of the mainstream media for 2010 in big trouble today.

There is a runoff in Oklahoma that has mostly caused a discussion there about why spending $900,000 to select party nominees in low-turnout two-round affairs is worth doing. Look for Oklahoma to be the next state to drop the runoff system.

Check Fox News' full Days to Decide coverage here.

Chris Stirewalt joined Fox News Channel (FNC) in July of 2010 and serves as digital politics editor based in Washington, D.C.  Additionally, he authors the daily "Fox News First" political news note and hosts "Power Play," a feature video series, on FoxNews.com. Stirewalt makes frequent appearances on the network, including "The Kelly File," "Special Report with Bret Baier," and "Fox News Sunday with Chris Wallace."  He also provides expert political analysis for Fox News coverage of state, congressional and presidential elections.