The way Obamacare was originally set up was a two tier shell game when it came to paying for it. The paying for it part was a complete lie on the Democrat's part.
The first part of Obamacare were the exchanges where people could buy individual policies. The system was set up to FORCE everyone not on an employer health insurance plan into those exchanges. What happened from that was:
Coverage generally got worse for most people buying a plan
The cost of the plans skyrocketed and options disappeared.
The subsidy of the policies was supposed to be done by insurers paying into a fund to cover losses from their profits. There were few profits and major losses by insurers. Many insurers pulled out of Obamacare for that reason leaving fewer plans in the system. The government was forced to make up the difference to keep the remaining insurers in the program.
The second part was the real disaster.
Obamacare also expanded Medicaid coverage optionally for states. The Democrats knew they couldn't force it on states legally. Blue Democrat run states bought in totally to this expansion. Few red states did likewise, opting for only some or parts of the expansion, or refusing entirely. To sweeten the pot, the Democrats set up the expansion so the feds picked up 70% of the cost initially and over 10 years this would decline to zero.
What happened there was the states that opted in couldn't pay for the expansion without massive tax increases. So, the Democrats in Congress kept the 70% subsidy in place with the expectation that eventually it would become permanent. It didn't and is now gone.
All of the expanded Medicaid resulted in about 25 million Americans getting a minimal health insurance coverage. Since virtually 100% of those now covered could pay NOTHING the whole plan had to be 100% subsidized. That is, socialized health insurance, something the Democrats totally denied was the case at the time Obamacare passed.
The result is the Democrats are in a panic that Obamacare is about to collapse because it isn't getting funded with perpetual subsidies that were never intended to be perpetual (eg., the Democrats lied their asses off about how Obamacare would work and now are facing the disaster they created).
To CYA their fuck ups, the Democrats are demanding $1.5 trillion in new spending to reopen the government. They, and they alone, created this mess and they don't want to own up to it. Instead, they want to just spend their way out of the situation long enough to retire from office. Then it's somebody else's problem.