Let's call Friday the unofficial kickoff of the DFL campaign for governor, when candidates will appear in Duluth at a forum put on by the American Federation of State County and Municipal Employees (AFSCME).

The endorsement of the 43,000-member union of public workers will be one of the most important of the race given the union's organizational muscle, money and motivation. The public employee unions have much to lose if Republicans retain their hold on the Legislature while winning the governor's race. They fear a Republican governor and Legislature would strip their collective bargaining rights and make Minnesota more like Wisconsin under Gov. Scott Walker, where unions have been denuded of money, members and influence.

The AFSCME news release on the event was blunt: "Republican candidates were not invited."

Prediction: The public workers in attendance, who have grown accustomed to a stream of vitriol from their opponents around the Capitol, will be praised to the point of flattery by the six DFL candidates hoping to win their backing.

Race for the House

With all the early attention on the governor's race, it's easy to forget that Minnesotans will choose 134 members of the House next year. The state Senate will not stand for election until 2020.

Some key numbers, noted recently by reporter David Montgomery: Seven DFL House members are in districts that President Donald Trump won in 2016, while a dozen Republicans are in districts Hillary Clinton won.

A Republican operative said they are optimistic, even if the national political outlook isn't great for the party. A wave of retirements in those GOP-Clinton districts would hurt, but their pitch to GOP lawmakers who are considering retirement is this: Don't leave office now, just as Republicans are on the cusp of full control of state government. And, expect Republicans to go on the offense in those DFL-Trump districts.

Winning the House is an uphill climb for the DFL: Flip 11 out of 12 of the Clinton districts, and hold all seven of the Trump districts they now control. A DFL operative conceded to me recently that the House is a two-cycle project.

But Susie Merthan, a spokeswoman for the House DFL, said stranger things have happened. "The average swing in a midterm election here is 17 seats. In an anti-Trump year, which is increasingly likely, winning the Clinton districts certainly seems possible. The Republicans are on more borrowed ground than the Democrats," she wrote in an e-mail.

J. Patrick Coolican • 651-925-5042 patrick.coolican@startribune.com Twitter: @jpcoolican