Timing is everything.

When new minimum wage laws are passed the increases are often incremented over a few years. This could cause unforeseen problems when the raise actually happens if the economy is on a downturn or the current market situation is different than what Congress was expecting when they passed the law.
When these laws are first taking effect businesses may be at an unfair advantage in the global market because of the sudden cost increase. If prices for goods produced in the U.S. suddenly go up this could cause global demand for our products to shrink which in turn shrinks our exports and our economy.