At the rate things are going, the best way for investors to play the upcoming brawl in the U.S. Senate over cap-and-trade may be to buy shares of the very companies this carbon-busting legislation is intended to squeeze out of business.

We’re talking the big coal-mining companies: Peabody Energy Corp. ( ), Arch Coal Inc. ( ), Massey Energy Co. ( ) and CONSOL Energy Inc. ( ).

This counter-intuitive investment strategy really isn’t counter intuitive at all when you “dig” beneath the surface.

As the New York Times pointed out in a July 22 editorial, the House-passed cap-and-trade bill, while it imposes a cap “from all industrial facilities that tightens slowly over time,” does not “impose any performance standards on existing (coal) power plants.” Moreover, the House version “explicitly removes these plants from the reach of the Clean Air Act.” In short, the Times laments, the House bill doesn’t “impose lower-emissions standards on the older, dirtiest plants.”

As Kate Sheppard recently wrote on Grist.org, the Senate may ratchet up the irony by cushioning the coal industry even more than the House has. “The coal industry got a lot of goodies in the House-passed energy and climate bill,” Sheppard wrote, “but it’s pressing for even more in the Senate version.” Among other things, the coal industry wants more for sequestration technology (even though it’s already getting some $60 billion under the House version), and it wants the gravy train known as free pollution credits to last longer than the House has prescribed.

Having been bloodied by the healthcare debate, and in desperate need to go to the Copenhagen climate conference in December with a mandate from Congress, logic strongly suggests that Obama will accept whatever the Senate does to further water down the anti-coal aspects of cap-and-trade, even as he publicly denounces anyone who charges that he “sold out” to the coal lobby.

While some investors will no doubt be scared away from coal by the heated rhetoric, the smart play here likely will be to bet on King Coal keeping his crown, at least for now.