The fight over the minimum wage, which President Obama and Democrats hope to make a centerpiece of this year’s midterm elections, comes down to two simple arguments. Obama says low-income working Americans deserve a raise, while Republicans say raising the minimum wage would cost jobs.

It was a mostly theoretical argument until Feb. 12, when Obama signed an executive order raising the minimum wage for employees of federal contractors to $10.10 an hour from $7.25. “This will make a difference for folks,” Obama said at a White House signing ceremony. “Right now, there’s a dishwasher at Randolph Air Force Base in Texas making $7.76 an hour — $7.76 an hour. There’s a fast-food worker at Andrews, right down the street, making $8.91 an hour. There’s a laundry worker at Camp Dodge in Iowa making $9.03 an hour. Once I sign this order, starting next year, as their contracts come up, each of them and many of their fellow coworkers are going to get a raise.”