Here's why Congress exempted itself from the new healthcare bill
This provision was bad "optics," as they say in Washington.
But instead of taking it out (like you would usually do with a provision you aren't wedded to and can't defend politically) the House passed the American Health Care Act with the exemption intact, after first passing an entirely separate bill that would repeal the exemption that would be created in the AHCA, if both bills became law.
There's a reason for this mess, and it's not about Republicans in Congress not wanting to be subject to their own law.
It's about Senate procedure.
As you may have read, Republicans are attempting to pass the AHCA through a process called "reconciliation." This process, created by the Congressional Budget Act of 1974, allows the Senate to pass certain bills relating to the federal budget with just a simple majority. There is no need to get 60 votes (and, in this case, some Democratic support) as there is for other legislation.
There are a variety of complex rules governing what matters may and may not be considered through reconciliation.
One of those is that reconciliation must be conducted pursuant to reconciliation instructions passed by both chambers of Congress. That happened earlier this year: Congress sent reconciliation instructions to two Senate committees (Finance; and Health, Education, Labor and Pensions) that were designed to allow those committees to write bills making changes to healthcare policy.
The problem, as the Committee for a Responsible Federal Budget explains, is that Congress' own healthcare is governed by the Senate Homeland Security and Government Affairs Committee, and that committee was not sent any reconciliation instructions.
Therefore, if a reconciliation bill makes changes to the way Congress gets its healthcare, it might become subject to a 60-vote threshold, because it addresses a matter that is supposed to be the purview of a committee that doesn't get to participate in reconciliation this year.
Why would the AHCA need to touch Congress' healthcare in the first place? Because Obamacare included, at Republican urging, a provision requiring members of Congress and their staffs to buy insurance through the Obamacare exchanges.
That Republicans are in this position at all reflects how rushed and ad-hoc their healthcare policy making process has been. They set about passing reconciliation instructions right after taking office because they hoped to repeal Obamacare very quickly. Since they didn't know what their eventual repeal strategy would be, they didn't know which committees would ultimately need reconciliation instructions, and now it's too late for them to change which ones have them.
Now, their hope is to enact the AHCA and the companion bill that undoes the congressional exemption created by the AHCA. That companion passed the House on Thursday unanimously with Democratic and Republican votes.
In the Senate, that bill would need 60 votes to pass, because it's not a reconciliation matter.
Democrats clearly like the talking point that Republicans exempted Congress from the AHCA - and if the AHCA gets enacted, Democrats will have the power to filibuster the companion bill and make it true as a matter of law. But politically, I'm not sure how it would land, as Republicans could say they are trying to apply the AHCA to Congress and it's Democrats who are blocking that simple bill from becoming law.
Of course, in all likelihood the Senate will pass a healthcare bill that differs extensively from the AHCA, which might make moot the whole matter of needing to change the rules about Congress' healthcare.