ST. PAUL (AP) -- Minnesota voters will provide a critical early readout on the state's wide-open governor's race during precinct caucuses.

The caucuses Tuesday are expected to be heavily attended by members of both parties. They 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.

History shows that poll is rarely indicative of who will win each party's nomination.

Party chairs are hoping high energy surrounding the state's politics powers high turnout 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.