Its called a veto. Look it up.<quoted text>
The point is that Obama, as President, has limited powers and has no right to demand anything.
The negotiation of any deal should be within the Congress, with Obama having the power to accept or reject the final compromise. When Obama states that certain elements are non-negotiable, he exceeds his power.
He can tell Congress that there are some actions that he will veto.
It is well within his powers to do so.