What Boehner meant is that any deal drawn up by the supercommittee would be scored by the Congressional Budget Office against a future in which the Bush tax cuts are supposed to expire. So if the committee tried to raise tax rates, they’d have to raise them by more than the cost of the Bush tax cuts if they were going to raise any revenues. This would require raising taxes by more than $3.5 trillion — an obvious non-starter. Thus, he argued, it would be effectively impossible to raise taxes.

But that’s not quite right. The baseline would just make it difficult to raise tax rates — which is how McConnell explained it when he sold the deal to Senate Republicans. But there are plenty of ways to raise taxes that don’t include raising marginal tax rates. The joint committee could cut loopholes and cap expenditures and the Congressional Budget Office would score that as raising revenues. They could recommend a value-added tax or a carbon tax and that would raise revenues. Republicans know this perfectly well, as this is the approach to raising taxes that they rejected during the debt-ceiling negotiations.

But it’s almost beside the point. The implication of Boehner’s comments is that the Congressional Budget Office is the word of God, and the word of God cannot be broken. But the Congressional Budget Office can be, and routinely is, ignored. The House Budget Committee, for instance, built its repeal of the health-care law around a baseline its members made up in which the health-care law cost more money. The Gang of Six and the Ryan budget and Obama’s April budget all measured their savings against a baseline that extends many of the Bush tax cuts and that people think is more realistic than the current-law baseline. If either the House or Senate Budget Committees, or the House or Senate leadership, asked the Congressional Budget Office to show how the joint committee’s cuts scored against some alternative baseline, they would happily do so.

The Congressional Budget Office offers analysis. That’s all it does. Congress can take its advice into account, it can ask for an analysis done from a different angle, or it can ignore the analysis altogether. Boehner wanted to convince his members that some outside authority would make tax increases impossible, but that not only isn’t true, it can’t be true. It would be unconstitutional.

Congress, after all, has sole authority to raise and lower taxes. It can reject anything the joint committee comes up with no matter what the CBO says about it. It could repeal the law it passed this week and set entirely different rules for the spending trigger. It could vote to raise marginal tax rates, and it could score that against some baseline the Budget Committee made up, and it could say it was reducing the deficit. It’s Congress. It can’t pretend this is somebody else’s job, or that the ultimate authority lies with some other body.

Which is why it’s so peculiar that Boehner even felt the need to make that argument. He could have simply released a joint statement with McConnell saying neither one would appoint anybody who would raise taxes, and nothing that raised taxes would garner any Republican votes in Congress. So one of two things is going on here: Either Boehner’s members still don’t trust that he’ll hold the line against taxes, or he’s trying to redefine a “tax increase” as something that increases marginal tax rates, rather than something that increases revenues. But either way, whether taxes go down or up has nothing to do with the Congressional Budget Office. It’s entirely up to Congress.