More than most Republican contenders for the presidency, Wisconsin Gov. Scott Walker, who made his official entrance into the campaign Monday, is known for his style of politics – combative – rather than the substance of his views. He regales conservative audiences with his success in defeating public unions in his home state and surviving three tough elections.

Winning elections takes political skill, but toughness is more complex. In an era of stagnant middle-class wages, declining unionization and soft labor markets, it’s not clear that unions posed the toughest threat to prosperity in Wisconsin.

It’s also unclear how Walker’s brand of toughness applies to the presidency. He has claimed that when President Reagan broke an air-traffic controllers’ strike in 1981, it marked “the beginning of the end of the Cold War.” And he has equated his own defeat of public unions in Wisconsin with his capacity to defeat the Islamic State.

It is difficult to overstate how dubious such claims are.

Now that he’s officially in the contest, Walker should assume he’s already made his case on style: Granted, he’s tough. It’s time to move on to substance.