they'll raise prices. that may or may not spell trouble for the affected businesses. Burger King competes with McD's et ali, and if one has to raise their prices, so will the rest. I'm not sure Joe McFatass would stop buying their burgers if a super sized mega-fat-meal cost say $7 instead of $5.50.
It's been years since the minimum wage was increased and certainly that means there's a lot of inflation (compounded) to catch up to in that gap. When minimum wage was last raised our economy hardly went belly up, and if we raise it to be equal (in dollars accounting for inflation) to the last hike, I doubt we'd see anything drastic happen.
Also, many states and local jurisdictions have increased minimum wage above the federal limit. Nothing terrible has happened in those areas.
I agree that it would be catastrophic to raise the minimum wage to a "living wage", but I doubt bumping it up to $6 or $7 an hour will do much damage.
What I would really like to see though is enforcement of minimum wage for illegal aliens with heavy fines for violations. I wonder if it would put a dent in our "illegal immigration problem" if employers had to pay $7 to Jose fruit picker plus social security and medicare taxes...