Republicans reduced the fee for not having coverage to zero, then took the ACA to court charging the mandate was illegal, then won because the fee was reduced to zero.
Let me say that again in a bit more detail:
The reason the ACA was ruled constitutional in a 2012 Supreme Court Case was because the constitutionality of the individual mandate to have coverage or pay a fee relied on that fee being a tax.
Congress has the power to tax, so the mandate was constitutional.
The mandate was constitutional, and so there was no room to declare the rest of the law unconstitutional.
The ACA won 2012 (although the mandate for Medicaid expansion took a hit).
However, Republicans in congress reduced the penalty for not having coverage to zero dollars as part of the tax overhaul that President Trump signed last December.
That means there is effectively no federal tax.
Without a tax, the argument from 2012 is weakened and it leaves the ACA vulnerable.
That vulnerable was then attacked by the Republicans using the legal system. First 20 Republican led states led by Texas banded together in a lawsuit charging that the mandate was illegal.
The federal government, Trump and his HHS, refused to defend the ACA (it is common practice for the administration in power to defend their own laws).
Republicans, with no administration to oppose them, were able to get their case heard…. in front of a Texas judge.
Judge O’Connor, a George W. Bush appointee, took the setup and gave the Republicans what they have loudly stated they wanted for years.
The judge ruled the mandate wasn’t legal, because there was effectively no tax, and then went a step further ruling that thus the whole ACA was unconstitutional.
If that sounds absurd to you, then you’ll understand why many ACA supporters feel confident the ACA will win its appeal when liberal states fight back by appealing the decision.
The moral: When Republicans could not get a repeal and replace plan passed in Congress they vowed to “repeal and replace by other means.” This is what they meant, like they have done since day 1 with the ACA, Republicans have circumvented the legislative system, using the judicial (since day 1) and executive (since Trump took office) to break ObamaCare.