Voters head to the polls in Alaska, Arizona, Oklahoma and Vermont today. What’s on tap: Another member-versus-member primary, a runoff to decide who the nominees to replace Oklahoma’s only congressional Democrat will be, and a Senate primary that was once potentially competitive, but no longer looks that way.

Here are five things to watch for:

1. Will Schweikert defeat Quayle (and the GOP establishment)?


Freshman Republican Reps. Ben Quayle and David Schweikert are facing off in a contentious race that has attracted lots of attention inside and outside the lines of Arizona’s 6th district.

As the contest took shape, House Republican leadership began to hint at its preference for Quayle, prompting the anti-tax Club For Growth to warn House GOP leaders against choosing sides.

Lately, the race has been heated, with Quayle’s campaign criticizing Schweikert over a mailer charging that Quayle “goes both ways." The Quayle camp said the reference carries sexual connotations; Schweikert’s camp said it doesn't.

Either way, it was enough to prompt Sen. John McCain (R) to criticize the mailer, and endorse Quayle in the race. Schweikert, meanwhile, has sought to go on offense against Quayle on the issue of an overseas trip Quayle took part in that involved drinking and skinny-dipping (though Quayle says he was properly attired and had just one drink).

The predominant thinking among strategists watching the race is that Schweikert is expected to prevail. Schweikert prepared an early, diligent campaign effort, and a mid-July internal poll showed him leading Quayle by double digits.

2. Flake’s margin of victory

The only thing in doubt in Arizona’s Republican Senate primary is how big Rep. Jeff Flake will win.

Flake faces Wil Cardon, a self-funding businessman who has hit the congressman from the right with ads attacking him on immigration (Flake is a former advocate of comprehensive immigration reform). Flake lobbed an immigration attack right back at Cardon, and after spending over $4 million, looks headed toward a win.

A recent poll conducted for the Republican-leaning Western Representation PAC, a group that has not endorsed in the primary, showed Flake up by 48 points. What’s more, Cardon went dark on the airwaves at the start of the crucial early voting period.

Flake’s anticipated win is a victory for the Republican establishment, which would be pleased to see congressman take on Democrat Richard Carmona in the general election. Carmona, a former Bush Administration surgeon general who was recruited to run by President Obama, is one of Democrats’ highest-profile Senate candidates.

3. Who will be the nominees to replace Dan Boren?

Rep. Dan Boren, the only Democratic member of the Oklahoma congressional delegation, announced his intention to retire last year, putting his party in a tough spot in a very conservative district. The net result is one of the GOP’s best pickup opportunities this cycle.

Before the general election can begin, both parties still have to choose nominees. Both primaries advanced to runoffs, which will be decided today. On the Republican side, plumbing company owner Markwayne Mullin (awesome name!) faces state legislator George Faught. Mullin finished 19 points ahead of Faught in the primary. On the Democratic side, prosecutor Rob Wallace, who took a 46 percent plurality in the primary, is the establishment choice against first-time candidate Wayne Herriman, who took 42 percent of the vote.

How tough a task will it be for the Democratic nominee to win the district in November? John McCain won two out of every three voters there in the 2008 presidential race, so it’s a substantial challenge.

4. How will the Club For Growth do?

The anti-tax group has had a mixed record in 2012, with some big primary wins (Richard Mourdock in Indiana, Ted Cruz in Texas) and some bad losses (Don Stenberg in Nebraska, Mark Neumann in Wisconsin). Today, the group is watching three endorsed candidates in Arizona.

The Club endorsed Flake, Matt Salmon and Ron Gould. Salmon is a former congressman who is expected to win Arizona’s 5th district Republican primary, while Gould is a state senator running against freshman Republican Rep. Paul Gosar in the 4th district.

Gosar looks like he has an edge against Gould, with a late July internal poll showing the congressman up ten points. Gosar also landed an endorsement from Sarah Palin, who backed him during his 2010 race. Still, it’s worth keeping an eye on the Gosar-Gould race, with more than a third of voters undecided in Gosar’s poll.

5. Arizona’s 9th district primaries

The open race in this new district the state gained in reapportionment has attracted a crowded field of candidates on both sides. While it appears to favor Democrats in the general election, it could be competitive.

In the Democratic primary, the pro-abortion rights group EMILY’s List is backing former state senator Kyrsten Sinema against former state party chairman Andrei Cherny and state Senate Democratic leader David Schapira. The Republican field is comprised of seven candidates.