Regina H. Boone/AP Photo

WHO'S ON THE BALLOT? Today, voters cast ballots in Alaska and Wyoming. The marquee race to watch is a three-way bitter GOP Senate primary in our nation's 49th state. Alaskan voters will decide between the establishment front-runner, a tea partier with Sarah Palin's backing, and Alaska's lieutenant governor. Also in the state, a young upstart in an Alaskan primary tries to take on the longest-serving Republican in the House and there's a contentious ballot measure. In Wyoming, there's a Senate primary race that may be lower profile since Liz Cheney dropped out, but there's a g ubernatorial primary, and much more.

Here are five races to watch and one ballot measure to keep an eye on:

THE FROZEN PRIMARY: Alaska's Republican Senate primary is not only one of the most closely watched and contentious this cycle, it will also select the Republican nominee to face Democratic Sen. Mark Begich in November. WHY IT MATTERS: This race could decide control of the Senate and could be the tightest this cycle. There are three viable contenders and with little polling, Dan Sullivan may be the favored front-runner, but it's still anybody's game. Former Alaska Gov. Sarah Palin shook up the race Friday by backing tea party favorite, attorney Joe Miller. She backed him in 2010, but it's different this time around as Sullivan was her attorney general appointee in 2009. Before his time as Alaska's attorney general, Sullivan worked as a senior adviser to Secretary of State Condoleezza Rice. Sullivan, a lieutenant colonel in the Marine Reserves, is also an attorney and the former natural resources commissioner in the state. The front-runner has been dogged by his Ohio upbringing and his critics have called him a carpetbagger, although he's been here since 1997 (leaving once for seven years to work in Washington, D.C.) and neither of his opponents were born in the 49th state, unlike Begich. Miller moved just two years before in 1995 while Treadwell has been in the state 40 years. He's up against Miller, who was the 2010 GOP nominee when he beat Sen. Lisa Murkowski in a primary shocker. He lost when Murkowski ran a successful write-in campaign. Miller had spooked the GOP for awhile, refusing to rule out an independent bid if he didn't win on Tuesday, but last week he said he would back one of his Republican rivals if he loses the primary. The third candidate is Lt. Gov. Mead Treadwell who has been going door to door to try and sway voters. Sullivan, who is backed by establishment figures like Karl Rove, but also the Club for Growth, has bested his rivals in fundraising raising $4 million to Treadwell's $1.2 million and Miller's less than $328,000. He's also run television ads for months and has a more sophisticated get-out-the vote operation, which includes paid aides with national political experience on top of local volunteers. But, Alaska is notoriously difficult to poll and front-runner status may mean nothing when it comes to this Alaska brawl. Another possible factor: there are two Dan Sullivans on today's ballot. Yes, you read that right. There's the Dan Sullivan running for Senate and then the Dan Sullivan, currently the mayor of Anchorage who is running for lieutenant governor. Sullivan's Senate ads have had to waste precious seconds clarifying, but it is still confusing. Both are Republicans and this could play a complicating role today, but it's hard to tell now what that could be. The victor will not only face Begich, but also at least four other minor party candidates. Both the Libertarian and Alaskan Independence Party candidates have contested primaries and will be on the ballot in November, likely a help to Begich, who face no serious primary challenger Tuesday.

AN INCUMBENT CHALLENGE IN WYOMING: Gov. Matt Mead is seeking a second term, but he has two Republican challengers in today's GOP gubernatorial primary in Wyoming. WHY IT MATTERS: Mead is facing off against state superintendent of public instruction and tea party favorite Cindy Hill and Dr. Taylor Haynes, a rancher and retired urologist. Haynes has called for the removal of federal control from all land in the state. Mead has run against federal overreach in Wyoming and opposition to Obamacare, while Hill's candidacy is more of a personal cause and a hint at how contentious this primary has become. Her run is inspired by legislation Mead signed last year which removed her as the head of the state Department of Education after a series of problems. The Wyoming Supreme Court reversed her removal this year. The victor today will face Pete Gosar, the former Wyoming Democratic Party chairman, but the GOP winner is the likely general election victor as well because a Democrat hasn't held a statewide office in Wyoming in almost four years. Plus the GOP has over three times as many registered Republicans in the state. Mead is expected to win, but Hill may cut into his margin of victory more than an incumbent would like.

THE OTHERS:

ALASKA'S AT-LARGE HOUSE SEAT: In Alaska, everyone knows Rep. Don Young. He's Alaska's only member of the U.S. House and at 81 years old is currently the longest-serving Republican in the House. The newly engaged Young has been rebuked for violating House ethics rules, but is expected to easily advance over little-known GOP primary challengers today on his way to a 22nd term. There is a Democratic primary and 29-year old Ivy-League educated Forrest Dunbar is the favorite and has the backing of the state Democratic party. He faces perennial candidate Frank Vondersaar. Dunbar is a judge advocate general in the Alaska Army National Guard. He interned for then-Sen. Frank Murkowski when he was 17, spent two years in the Peace Corps in Kazakhstan, and has degrees from Yale Law School and Harvard's Kennedy School of Government. Young is still heavily favored in November and he has served in Congress longer than Dunbar has been alive. Dunbar runs on the slogan "Run, Forrest, Run" and argues the long-serving Young is no longer effective. Along with better care for veterans, Dunbar wants to make same-sex marriage legal in the 49th state. Young has raised over $631,000 to Dunbar's less than $94,000.

WYOMING SENATE REPUBLICAN PRIMARY: This race immediately became lower profile, less exciting, and much less contentious when Liz Cheney, daughter of former Vice President Dick Cheney, dropped her bid in January to challenge incumbent Sen. Mike Enzi. Her short-lived campaign was a political shocker when she decided to challenge Enzi, but after several missteps and even some family drama she abandoned her bid citing family health issues. Enzi now only faces token opposition from four GOP opponents including a self-described soldier of fortune, an oil company worker, a retired Air Force officer and energy consultant, and the fourth is a completely unknown candidate. There are also four Democrats: a former priest, a contractor worker, a retired sign painter and a fourth candidate from Brooklyn (yes, New York) vying for the chance to face Enzi, but in this red state, the incumbent is likely to sail to victory.

WYOMING'S AT-LARGE HOUSE SEAT: Like Alaska, Wyoming only has one U.S. House seat and incumbent GOP Rep. Cynthia Lummis, 59, is seeking a fourth term, but she is facing a political newcomer, Jason Senteney, today. Senteney, 36, is a corrections officer and volunteer firefighter. Lummis was first elected in 2008 and easily won re-election in 2010 and 2012. Senteney is running on support for a flat tax, while Lummis has decried what she calls federal overreach. It's likely Lummis will sail to victory and she has no Democratic candidate from Wyoming facing her in November. Richard Grayson, a Democrat and political gadfly from Arizona is on the ballot, but has already said he has no hope of winning.

WHAT ELSE ARE WE WATCHING?

ALASKA'S BALLOT MEASURE NUMBER ONE: Alaskans will also vote today to decide if the state's old system for taxing oil companies is better than the new system and it's stirred up passion and action on both sides. The old one championed by then-Gov. Sarah Palin passed in 2007 and it was her hallmark achievement in office. The new system was only passed last year and is pushed by current-Gov. Sean Parnell, who was her lieutenant governor and succeeded her when she resigned in 2009. The goal of Parnell's plan is to attract more investment from oil companies and what supporters say will increase drilling in the state's North Slope, where production has declined. It replaced the production tax created under Palin titled "Alaska's Clear and Equitable Share" or ACES. The oil companies hate Palin's plan with critics blasting the progressive surcharge as discouraging new investment in oil production. It has brought together the strange bedfellows of Palin and some of the most liberal lawmakers and residents of the 49th state. She weighed in last week on both her Facebook page and her new subscription web channel saying Parnell's law should be repealed and decrying "outside" influences. "We own the energy sources per our Constitution, and we violate our state's blueprint that creates security and prosperity when we wave the white flag and give in to every demand of multinational corporations doing business up here," Palin wrote. Supporters of ACES say the oil belongs to the state and it's the state, not oil companies, that should profit from the drilling in Alaska. Critics of Parnell's law says it gives massive tax breaks and incentives to the oil industry at the expense of revenues that could go to the state, while supporters say it needs more time to succeed and it will ensure jobs for Alaskans. The oil companies support Parnell's plan and have outspent the supporters of Palin's plan by 10 to 1. Under the state constitution oil resources are owned by state residents, but critics who want to repeal the new law say it could put that fact of Alaska life at risk in some circumstances. The ballot measure is so contentious and high profile it could actually boost voter turnout in traditionally low turnout primaries. The three GOP Senate candidates: Sullivan, Miller, and Treadwell all support staying with Parnell's plan while Begich has not weighed in, saying it's up to Alaskans to decide.

This story has been updated since it was first posted.