ST. PAUL — Jeff Johnson has become the punching bag in the Minnesota Republican primary for governor — and he’s just fine with that.

The Hennepin County commissioner is increasingly catching flak from three competitors. Johnson takes it as a sign he’s out front in a race that has gone months without a clear favorite. Tuesday’s primary winner will face Democratic Gov. Mark Dayton in November’s election.

“We knew that would happen, that whoever was behind would likely start going on the attack,” Johnson said Thursday. “But it’s getting late and I don’t think it’s going to affect things all that much.”

First it was businessman Scott Honour, who sharply questioned whether Johnson would be bold enough when it comes to cutting the state budget and reducing the might of organized labor. Former state Rep. Marty Seifert has made a point in recent days of emphasizing Johnson’s blowout loss in the 2006 attorney general race as a sign he could have general election trouble. Rep. Kurt Zellers, the former House speaker, has repeatedly swung at Johnson over his openness to expand the state sales tax to more items as long as the tax rate is simultaneously cut.

The candidates are done with their pre-primary debates. One that had been set for Thursday night on WCCO Radio got canceled after Zellers and Honour said they wouldn’t debate if Johnson wasn’t there. Johnson, who has the Republican Party’s convention endorsement, cited a scheduling conflict in declining to participate.

Many people, including the candidates, are predicting a small turnout in the party’s first competitive primary for governor in 20 years. So it wouldn’t take a substantial shift in votes to change the winning order next week.

In a news release Thursday, Zellers compared the sales tax idea to one Dayton pursued then abandoned in 2013 in the face of bipartisan opposition. Dayton’s expansion would have subjected a raft of services to the tax but would have also lowered the rate.

“Even if he claims it is revenue neutral, the bottom line is that someone is going to pay more — paying a tax on a service or good that was previously untaxed,” Zellers said of his GOP opponent. “Jeff Johnson is carrying the same tired ideas that Mark Dayton tried to force on Minnesotans just last year.”

Johnson, who is also a former legislator, insists any tax changes would be crafted so the state takes in no more money than it would under the old setup.

“That would be the first time anyone has compared me to Mark Dayton this entire race when it comes to budgeting philosophy and tax philosophy,” he said. “We are as far apart as you can get, Mark Dayton and I.”