ST. PAUL, Minn. (AP) — Minnesota voters will provide a critical early readout on the state's wide-open governor's race during precinct caucuses Tuesday that are expected to be heavily attended by members of both parties.

The caucuses mark the first step in the march toward each party's nominating convention in June, with the main event a preference poll testing support for all gubernatorial candidates. But in a year that will also see a special election for former Sen. Al Franken's seat and four or more closely watched congressional races, party chairs are hoping high energy surrounding the state's politics powers high turnout.

"For the first time in many years, we truly are going to be at the forefront of national politics in this election cycle in 2018," Republican Party Chairwoman Jennifer Carnahan said.

Republicans are aiming to ride momentum from 2016 — when President Donald Trump nearly became the first GOP nominee to win Minnesota in four decades — to break through and win a statewide race for the first time since 2006. And Democrats are hoping to energize voters to lead a backlash against the president and his party in Minnesota.

But while voters from both parties begin to organize for two U.S. Senate races, congressional campaigns and a battle for control of the state House, the preference poll on Tuesday will only be taken for the governor's race. It's a wide-open contest to replace Gov. Mark Dayton, netting six major Democratic candidates and a still-unsettled field for Republicans.

History shows that poll is rarely indicative of who will win each party's nomination. Former House Minority Leader Marty Seifert won the polls in both 2010 and 2014 but lost the GOP endorsement both years. Dayton didn't even put his name on the ballot ahead of his first election in 2010.

"It's a little bit of a beauty contest," Democratic Party Chairman Ken Martin said. "It is important for the candidates and their campaigns to be able to show their political muscle."

Rep. Tim Walz, St. Paul Mayor Chris Coleman, State Auditor Rebecca Otto and state Reps. Tina Liebling, Paul Thissen and Erin Murphy will be on the ballot at Democratic caucuses.

But there's an extra wrinkle for Republicans that could cloud Tuesday's voting: Former Gov. Tim Pawlenty may enter the race. Brian McClung, a former top aide and longtime adviser to the two-term governor, confirmed last week that Pawlenty planned to convene a meeting with his inner circle next week to discuss the race. GOP candidates struggled with fundraising in 2017, and Pawlenty's strong name recognition and fundraising prowess would make him an alluring candidate.

Carnahan said his candidacy "would add a new dimension to the Republican side." Neither party is allowing write-ins during the caucuses Tuesday.

Hennepin County Commissioner and 2014 nominee Jeff Johnson, former party chair Keith Downey, Woodbury Mayor Mary Giuliani-Stephens, Phillip Parrish and Lance Johnson are on Tuesday's ballot.

The caucuses are also the start of building party platforms and electing delegates who will eventually decide their party's endorsements, but Tuesday's results aren't binding. Republicans and Democrats are set to hold their statewide conventions starting June 1.

Caucuses begin at 7 p.m. and the poll in the governor's race is the first order of business. Find your caucus location here.