It's misleading to state that SS has a $2.7 trillion surplus. There is no fund that benefits are extracted from. The 'surplus' is the projected revenue that will be collected before it goes in the red. Government already spent the SS fund. Current benefits are paid out with current tax dollars, it's only shading accounting that allows politicians to say with a straight face that SS doesn't contribute to the debt.
The welfare of humanity is always the alibi of tyrants