Sen. Lindsey Graham remarked that the Senate GOP healthcare bill revealed Thursday has a one-in-two chance of being passed by the upper chamber.

"It's 50/50 we get to 50," Graham, R-S.C., said at the annual congressional picnic at the White House, according to CNN's Steve Brusk. The senator was referring to the 50 GOP votes needed to pass the bill under the process of reconciliation, with a tie-breaker vote from Vice President Mike Pence.

Earlier in the day Graham tweeted that he would "carefully review" the legislation before making a decision. Already four of 52 Republicans, Sens. Ted Cruz of Texas, Ron Johnson of Wisconsin, Mike Lee of Utah and Rand Paul of Kentucky, have said they are "not ready" to support the bill in its current form.