Sens. Lindsey Graham (R-S.C.) and Chris Van Hollen (D-Md.) released an outline of potential sanctions against Turkey on Wednesday, following the news of a Turkish military offensive against Kurdish forces in northern Syria.The big picture: Few announcements from the Trump White House have engendered such bipartisan outrage as the news that Turkey was preparing to attack Kurdish forces in Syria — and that the U.S. would be getting out of the way, according to Axios' Dave Lawler.The state of play: The senators say their sanctions will go into effect upon enactment unless the Trump administration confirms that "Turkey is not operating unilaterally" in Syria and has withdrawn its armed forces from areas it occupied as of Wednesday.Graham told Axios' Jonathan Swan that he predicts he will have more than enough votes to override a presidential veto of the sanctions, saying: "Who the hell supports Erdogan over the Kurds?"Turkey said on Wednesday that its ground forces have crossed into northeastern Syria. The Kurds, which allied with the U.S. in 2015 to fight ISIS, have long feared that Turkey would cross the border and wipe them out if U.S. troops left the region.What they're saying: Graham believes Trump is making the biggest mistake of his presidency by withdrawing troops from the region."This is worse than when Obama left Iraq, because you've got so much information as to what happens. This would be a game changer to our national security. This would pave the way to the re-emergence of ISIS," Graham said.Read the outline: Go deeper: Turkey's Syria offensive puts alliance with U.S. near breaking point