On Monday night, as the Senate Republican health care bill floundered in the wake of two defections that were more than enough to kill the bill, Washington Post reporter Robert Costa took to Twitter to explain the inside story of why congressional Republicans are comfortable with failing to repeal Obamacare.

For Costa, the apparent death of the Senate bill represents a reevaluation of the political calculus of repealing Obamacare — a law that, over time, put down “roots” in many states and is currently twice as popular as the Senate health care bill, according to the Washington Post/ABC News poll released this week.

Costa says Republicans in the House and Senate have told him they hope to show their efforts at repeal and then “blame Dems” for the failure of the bill, giving them the political boost of repealing Obamacare among hardline conservative without the fallout of actually passing the deeply unpopular bill.

While some Republicans had publicly used the excuse that failing to repeal Obamacare would be costly in the 2018 midterms, they have privately told Costa they oppose the current plan. This reevaluation might be wise given recent polling, which showed support for the bill was toxic among voters.

A few thoughts on the health-care stall tonight in the Senate... — Robert Costa (@costareports) July 18, 2017

An ideologically-driven GOP leadership is confronting the reality of a law that now has roots in states, fading as rally cry for base. — Robert Costa (@costareports) July 18, 2017

Most elected Rs don't fear primary challenge if they buck repeal. They see base's ire as grievance/"fake news" focused, not ACA obsessed. — Robert Costa (@costareports) July 18, 2017

Trump's sale was limited, as were threats for foes. A little chatter about Flake, a few tweets, brief ad war with Heller. That's it. — Robert Costa (@costareports) July 18, 2017

Privately, several House mbrs and Sns told me for weeks they didn't really want to pass it. Like groom w/ cold feet, after long engagement. — Robert Costa (@costareports) July 18, 2017

What many Rs wanted was to check box without political cost. Passionless effort. Saw Dems salivating at what passage meant for '18. Cringed. — Robert Costa (@costareports) July 18, 2017

What you have to understand is that privately many Rs rather "blame Dems" ahead of 2018, rather than shoulder burden of passing this bill. — Robert Costa (@costareports) July 18, 2017

Last night, Sens. Mike Lee (R-UT) and Jerry Moran (R-KS) announced via Twitter that they would oppose the motion to proceed with the bill, joining Sens. Susan Collins (R-ME) and Rand Paul (R-KY) to effectively kill the bill.

My colleague @JerryMoran and I will not support the MTP to this version of BCRA #HealthcareBill — Mike Lee (@SenMikeLee) July 18, 2017

My colleague @SenMikeLee and I will not support the MTP to this version of BCRA. #HealthcareBill — Jerry Moran (@JerryMoran) July 18, 2017

As Vox’s Dylan Scott noted, Lee’s opposition appeared to be based around uncertainty about the impact of the Cruz amendment — which allowed the sale of plans that didn’t meet the Affordable Care Act regulations — and the potential development of two insurance pools.

Importantly, three of the four senators who blocked the bill — Paul, Lee, and Moran —- are some of the more conservative members of the caucus and oppose the plan on the grounds that it doesn’t go far enough, something Vox’s Matt Yglesias suggested could remain a problem for Obamacare.

It remains to be seen whether the Republican effort to repeal and replace Obamacare is actually dead or whether, as Yglesias said, only this version of the bill has died.