And National knows it. Once the Prime Minister declared on Monday that the Supreme Court ruling had put some 40 court trials at risk and "some very serious criminals could walk free", the debate was over for Labour before it had even begun.
Labour has little choice but to back the bill, even if National could get the numbers in Parliament from other quarters - something which was still unclear last night.
One of National's support partners, the Maori Party, was making it pretty obvious it could not vote for the bill.
Act, National's other partner, was last night still deciding what to do. The party might well regard the bill's infringement of the Bill of Rights as beyond the pale. But it could take a different tack, given its strong push on law and order.
The Greens will also oppose the measure out of principle.
This is a case where minor parties have the luxury of being able to play to their audiences. Not so the major Opposition party. In such a situation, it is expected to take what most people would see as the responsible position and weigh in behind the Government. It would get the blame if just one trial was aborted because its votes had stymied the emergency legislation.
Labour cannot afford that. It was still making its dislike of the bill it has yet to see pretty plain yesterday. It was insisting that the measure be subject to select committee scrutiny, brief as that might have to be.
All in all, Labour was making clear its objections to the way National was handling things. But this amounts to little more than political window dressing prior to the party inevitably falling into line.