Yep, they're serious about grandstanding on something like this - and, in my view, it could be a defining moment for nihilist Republicanism. Bruce Bartlett was onto this before most of us:
Frum tries to find a way out for the GOP.
As far as I am aware, no other country on Earth has the idiotic policy that the United States has of having a legal limit on the amount of bonds the central government can issue. They correctly recognize that the deficit and the debt are simply residuals resulting from the government’s tax and spending policies. It makes no sense to treat the debt as if it is an independent variable.
Some argue that the debt limit has the virtue of focusing the attention of policymakers on the debt. But Congress already has a budget process designed to do that on an annual basis. Having a separate debate on the debt limit is at best superfluous. But it’s also dangerous because it allows members of Congress to try and compensate for being fiscally irresponsible voting for new entitlement programs such as Medicare Part D or massive tax cuts that are not offset with spending cuts by casting a vote against the debt limit.