More than enacting healthcare policies the public rejects, senior Republican strategists fear the political consequences of doing nothing at all, fretting that failing to repeal Obamacare will be an albatross in 2018.

The Republican Party's various proposals to replace President Barack Obama's signature healtcare overhaul have never polled well. Indeed, insecurity over how healthcare might change under President Trump has led to the Affordable Care Act's best ratings since it passed over seven years ago.

But dumping Obamacare remains a top priority for committed Republicans, and GOP insiders who monitor voters' attitudes were warning Friday after the latest repeal bid appeared to collapse that the party was sewing the seeds for a midterm rebuke.

"The failure to deliver on Obamacare is deeply felt by the Republican base. It symbolizes everything that Republican base voters don't like about Republicans in Washington," said Steven Law, who is close with Senate Majority Leader Mitch McConnell, R-Ky., and runs his affiliated super PAC, the Senate Leadership Fund.

"There's a very clear divide developing between how Republicans feel about the president and how they feel about Congress, and a key flashpoint is the Republican Congress' failure to pass anything that looks like dismantling Obamacare," Law added, during a brief interview with the Washington Examiner.

The House approved legislation to partially repeal Obamacare in the spring. A similar effort stalled in the Senate over the summer but was revived this month when a package sponsored by Sens. Bill Cassidy, R-La., and Lindsey Graham, R-S.C., appeared to be gaining traction.

That effort was derailed Friday when Sen. John McCain, R-Ariz., whose "no" vote sank the previous Senate bill, announced his opposition to Graham-Cassidy, which was cosponsored by Sens. Dean Heller, R-Nev., and Ron Johnson, R-Wis. Without McCain, Republicans are at least one vote shy of the 50 they need to clear a repeal bill, with no obvious place to turn to make it up.

Sens. Susan Collins, R-Maine, and Rand Paul, R-Ky., already opposed Graham-Cassidy, and Sen. Lisa Murkowski, R-Alaska, was on the fence but did not appear enthusiastic about the legislation. If Republicans can't get to 50 votes under the reconciliation rules that allow them to sidestep a Democratic filibuster, Vice President Mike Pence's tie-breaking vote is useless.

"This was a boulder pushed by the White House and Lindsey Graham that should never have been discussed unless they had McCain and Murkowski to begin with," said a Republican insider in Washington, who requested anonymity in order to speak candidly.

The episode is causing fresh anxiety among Republican strategists focused on 2018 who worry that the party is exposed to a Democratic takeover.

Pivoting from their first healthcare debacle to successfully passing tax reform might have assuaged angry GOP voters. Now, some Republicans worry that the Obamacare wound has been re-opened.

Republicans have been promising to "repeal and replace" the Affordable Care Act since Obama signed it into law more than seven years ago. The promise helped propel Republicans to a House majority in 2010, a Senate majority in 2014, and control of the White House in 2016. So far, they have failed to make good on this commitment.

Republican voters' opinion of Congress has tanked as a result, and GOP powerbrokers worry that inability to deliver while in full control of government will enrage the grassroots and depress turnout of a broader electorate that could wonder what's the point of reelecting a Republican House and Senate.

Some are pointing fingers at Paul, and are hoping to put enough pressure on the Tea Party libertarian from Kentucky to change his mind over the next few days. If Murkowski supported support Graham-Cassidy and Paul flipped, it would reach the 50-vote threshold it needs to pass.

"Every Republican senator needs to make clear to Rand Paul that this changes their relationship with him forever. It is one thing for a moderate to sink a conservative priority, but it is completely unacceptable for a conservative to sink a conservative priority," a GOP operative said. "If the senator opposes [Graham-Cassidy], he will have to spend the rest of his career explaining why he prefers Obamacare to this. Everything he's ever done will fade away, and this will be his legacy."