Well, here it finally is: the long-threatened “bipartisan” comprehensive immigration reform proposal, and as the old joke has it, when the Stupid Party and the Evil Party get together, they come up with something that is both stupid and evil.

The principles underlying the proposal (the actual bill will ascend from the depths next month) have been conveniently laid out by the senatorial “Gang of Eight.” If after reading them you feel an irresistible urge to send your bank-account number and a power of attorney to an e-mail account in Nigeria, or experience similar symptoms, you are advised to consult comments on the proposal from Mark Krikorian, from Charles C. W. Cooke, and from long-time Democrat activist and former New Republic writer Mickey Kaus.

Between them, Mark and Mickey more or less demolish the policy arguments — pretexts really — within the proposed legislation as slippery, dishonest, and damaging socially and economically, while Charlie shreds the argument that Republicans should pass it even so for reasons of political self-interest. While I will have more to add on these specifics as the debate develops, I want to suggest the most important point for now: Defeating this legislation should be the main purpose of the conservative movement in the next twelve months. Here are a few reasons why:

First, it’s a terrible piece of legislation and it deserves to be halted in its tracks. It will make some of America’s problems much worse without solving or ameliorating others. Opposing the legislation is an act of patriotism and political hygiene. Some conservatives currently doubt this and will want to be persuaded of its truth before signing onto the campaign to derail it. That is something that the bill’s opponents will have to do in detail and with evidence over the next few months. For the moment, however, we should state clearly the simple truth: This bill is both stupid and evil and we’re against it.

Second, the conservative movement needs a good fight to get it off the canvas. This is a good fight and it’s a fight for the good. We should relish it.

Third, the supporters of the bill are utterly confident of victory. They believe that they have steam-rolled Republicans and conservatives into accepting this dreadful legislation as inevitable. They have already ordered the champagne for the victory party. So the bill’s defeat would be correspondingly unsettling — no, frightening — for them. It would cast a pall of doubt over their conviction that America is now a liberal progressive country. And it would be thoroughly encouraging for every conservative, and for every opponent of every liberal measure in the Obama administration’s legislative quiver.

Fourth . . . and if we lose in the end? Well, no one now expects us to win. The practical consequences for America of bad legislation will be tragic, of course, but our consciences will be clear, and our foresight and wisdom will be increasingly obvious as those consequences unroll. If our opponents emerge victorious but bleeding and divided, we will be far better off than if they had raced to a “bipartisan” triumph on chariots oiled by John McCain, Marco Rubio, Lindsey Graham, and Jeff Flake.