The Senate’s longshot Obamacare repeal bill is starting to look possible.

It gained more momentum Monday after receiving a big endorsement: Republican Arizona Gov. Doug Ducey.

The governor’s position matters because Sen. John McCain (R-AZ) has said his governor’s support was necessary for the senator to back the plan, which would bring it one vote closer to the magical number of 50.

Ducey said that he would support the bill from Sens. Bill Cassidy (R-LA) and Lindsey Graham (R-SC), which would turn much of Obamacare’s funding into block grants for states with few strings attached. The bill would also place a federal spending cap on Medicaid, which is jointly funded by the states and feds, for the first time. That has caused many governors, who administer Medicaid, to balk.

McCain has frequently conditioned his support for any Obamacare repeal bill on Ducey’s blessing.

McCain tells @GarrettHaake he wants bipartisan bill with wks of hearings. BUT may "reluctantly" back Graham-Cassidy if AZ Gov approves — Benjy Sarlin (@BenjySarlin) September 18, 2017

McCain will be one of the most closely watched votes on Cassidy-Graham, along with Sens. Susan Collins, Lisa Murkowski, and Rand Paul. Senate Republicans need 50 of their 52 members to pass the bill.

Cassidy and Graham are rushing to get the bill ready for a floor vote ahead of a September 30 deadline to pass the bill under the special “budget reconciliation” rules that allow a bill to advance with only 51 votes instead of the usual 60. Senate Majority Leader Mitch McConnell has indicated he will only put Cassidy-Graham on the Senate floor if he is sure it has 50 votes.

McCain has also objected to the process being used to produce the Obamacare repeal bills, none of which have gone through the usual committee hearings and mark-ups that produce legislation. As recently as Sunday, he warned that Republicans should not repeat the mistakes he thinks Democrats made in passing the health care law.

John McCain backs the bipartisan work on Obamacare fixes by Alexander and Murray. Pretty clear signal.https://t.co/dWU6Guvntw — Sahil Kapur (@sahilkapur) September 17, 2017

Sen. Ron Johnson (R-WI), one of Cassidy-Graham’s co-sponsors, announced he would hold a hearing next week on health care in the armed services and government affairs committee that he chairs, though that committee does not actually have jurisdiction over the Obamacare repeal bill. It is still likely a nod to McCain’s process concerns.

It is also worth noting that McCain also opposed so-called “skinny” repeal in late July, even though Ducey had given his blessing for the senator to support it, according to the Arizona Republic.

So Ducey’s endorsement does not absolutely assure McCain’s vote. Nevertheless, it is good news for Obamacare opponents as they try to build support for Cassidy-Graham in the coming days.