Wait a minute, he followed George Bush, not Bill Clinton

"Romney attacks Obama for not keeping unemployment below 4 percent"

Romney is ignorant.  All that needs to be said is what is written at that link:  "...No Republican president in the last 40 years has lowered the unemployment rate below 4 percent. "

If you want unemployment in the four percent range, you don't elect a Republican.  That is an historical fact.