Now that the EPA has laid the groundwork to go forward with its own set of greenhouse-gas regulations, p observers have suggested that this will put pressure on Congress to pass a climate bill next year, rather than leaving everything up to the executive branch. But is there any actual evidence of this pressure? Maybe so. Here's Arkansas Democrat Mark Pryor:

Sen. Mark Pryor, D-Ark., said today he may rethink his position on a proposed cap-and-trade program in light of the recent Environmental Protection Agency ruling that greenhouse gas emissions are a threat to the public health.

Also today, the chairman and CEO of Entergy Corp. told an audience in Little Rock the EPA has sent a signal to Congress to act on climate change, and U.S. Sen. Blanche Lincoln said she has concerns about the agency’s ruling.

"I’ve always been reluctant on cap and trade, but it (the EPA ruling) might put that in a different light," Pryor said in a conference call with reporters. "I’ll just have to look at that and really spend some time reflecting on that and talking to not just colleagues but talking to people who really understand this and see if that does change my view on cap-and-trade."

The ruling clears the way for the EPA to regulate carbon emissions under the Clean Air Act, though Congress could act first by passing legislation on climate control. In June the House passed a bill that includes a cap-and-trade program, in which credits or allowances permitting increases in emissions could be bought and sold between companies.

Pryor said he would rather see regulation of carbon emissions come from Congress than the EPA.