I do NOT believe that this was a slip of the tongue. I believe it was a test to see how the WH press corps would react. The communists are trying to read the pulse of the people regarding the idea of Obama openly acknowledged as the functional POTUS.
Everyone with more than 2 brain cells knows that Joe Biden is an empty suit - a marionette - a sock puppet. Almost everyone believed all along that it was Obama who was really running the dog and pony show.
It will be interesting to see how things develop over the next few months...I'm pretty sure they're preparing for the day when they announce that Biden "regretfully" is stepping down ...blah blah blah...

That was a Freudian slip.

At least she's being frank!