The House GOP has voted to repeal Obamacare 41 times, as of last count, but that link is from Sept.12 and maybe by now the number is higher yet. One can thus conclude that the GOP sees advantage in staking out a public position against Obamacare, whether this be with voters, donors, primary opponents, whatever.
By threatening a government shutdown over Obamacare defunding, the GOP is again staking out a public position against the law. Such a statement is more focal, and generates more publicity, than a 42nd vote for repeal. Everyone is talking about it, even me (sorry people). If you’ve voted 41 times for repeal, you will like the fact that everyone is concerned with this new dispute.
If the GOP lets the government actually shut down, people will talk about their Obamacare stance even more. But the party, and its representatives, will bear costs from being associated with the shutdown, which is inconvenient, hurts the economy, and lowers our international status. We don’t know whether they will cross this threshold, but either way it is a purely political calculation and not especially mysterious or “irrational.”
It seems to me that ideally the GOP would prefer to “negotiate” forever, without having to shut down the government at all, see this recent report.
The GOP also wishes to combat the notion that it is the intransigent party, and a battle over the relatively unpopular ACA (“why will Obama negotiate with Putin and Assad but not with us?”) is a better arena for them than most of the other venues where this clash of reputations might pop up.
The GOP, from its budget strategies, might manage to repeal the medical devices tax. Repealing a tax, and chipping away at ACA, is in this setting a major victory for them, especially given that right now they are not winning so many victories. It doesn’t matter so much that the medical device tax repeal would be relatively small in its impact. “We forced the repeal of one part of Obamacare” is a big symbolic victory.
Recent events are simply public choice theory in action.