On the heels of aggressive action from the League of Conservation Voters, Credo and FOE and Move On, the Sierra Club is now targeting Senator Lincoln with a radio ad:

The Sierra Club has launched a new radio ad campaign calling out Senator Blanche Lincoln (D-AR) for her decision to co-sponsor legislation that would undermine the Clean Air Act’s protections for public health and welfare and bailout big polluters at the expense of job-creating clean energy and cleaner burning natural gas. The 60-second radio spots, which began running yesterday, will run for two weeks in the Little Rock and Fort Smith media markets.

“Not only has Senator Lincoln helped stall comprehensive clean energy and climate legislation, now she wants to take us backwards and gut the Clean Air Act too,” said Carl Pope, Sierra Club Executive Director. “Senator Lincoln’s actions could prevent President Obama from protecting the well-documented threats to public health and welfare presented by global warming pollution. The legislation she supports would bail out Big Oil by halting the president’s plans to save 1.8 billion barrels of oil by increasing fuel economy standards and would also prevent the Environmental Protection Agency from cleaning up dirty coal plants and other big polluters like oil refineries. Senator Lincoln’s constituents ought to ask her why she wants to help Big Oil and out-of-state coal companies to the detriment of the clean energy businesses and natural gas industry that are actually creating jobs in her home state.”

Click here to listen to the add, or read the transcript below.

“Record job losses… foreclosures… rising costs… Arkansas is hurting.

“In these tough times, we need strong leaders to stand up to special interests, and help get our economy back on track.

“But NOW, instead of standing up for Arkansas’ future, Senator Blanche Lincoln is co-sponsoring legislation to roll back the Clean Air Act laws that protect us from polluters putting poison into the air we breathe.

“Health experts say that Lincoln’s action will undermine one of our country’s greatest health and environmental laws.

“They’re urging Senators to oppose it.

“And if this wasn’t bad enough, a major national newspaper reports that the legislation Lincoln supports was done at the behest of lobbyists.

“Senator Lincoln, it’s time to choose sides.

“Lobbyists and Washington insiders—or the health and welfare of Arkansas families?

“Call Senator Lincoln at 501-375-2993.

“Tell her Arkansas needs more jobs and clean air. NOT more favors for special interest lobbyists.

“Paid for by Sierra Club of Arkansas”

Lots of folks have taken note of new polling today showing John McCain potentially in trouble in next year’s Arizona Republican primary for his Senate seat.

Matt Yglesias flags an important aspect of this:

This seems like pretty much terrible news for the world. The most likely path between Point A and Senate passage of a reasonable climate bill is for McCain to rediscover his interest in the issue. But that’s not the sort of thing a Senator worried about a right-wing primary challenge is likely to do.

This is exactly right. And of course, a Politico story (where else?) provides the evidence:

Sens. Lindsey Graham and Joe Lieberman have been working overtime to craft a climate bill that can attract significant GOP support. But they aren’t exactly scoring points with their mutual best friend in the Senate, John McCain. “Their start has been horrendous,” McCain said Thursday. “Obviously, they’re going nowhere.”

This should not be a surprise for anyone who has been paying attention to McCain’s statements on climate legislation since last year’s election.

Steve Benen checked in with a McCain spokesperson on this and got an absurd response:

Asked for an explanation, McCain spokesperson Brooke Buchanan said, “This really hasn’t been done in a bipartisan fashion.”

I see. The climate bill is being pushed by a Dem (Kerry), a Republican (Graham), and an Independent (Lieberman), but the problem is that the effort is too partisan. Follow-up question for Brooke Buchanan: “Huh?”

Predictably, arbiter of conservative-leaning beltway conventional wisdom Chuck Todd blames President Obama for not reaching out enough.

There is a larger point to all of this though. Primary challenges are an extremely effective way to hold ‘moderate’ Members of Congress to the party line. Probably the single most effective way to do so, I’d say.

Arlen Specter is a great example of this (full disclosure: I can’t stand Arlen Specter):

Specter’s overall party loyalty score since becoming a Democrat — counting votes both before and after the primary challenge — is 87 percent. This contrasts with the 44 percent of the time that he broke ranks to side with the Democratic on Contentious Votes while still a member of the Republican Party. He’s basically been behaving like a mainline, liberal Democrat.

On the other hand, it’s hard not to imagine that this process has been strengthened, accentuated, catalyzed, by Joe Sestak’s primary challenge. You can draw a pretty clear line in the sand from when Specter went from sorta, kinda Democrat to OMG totally! Democrat, and it coincides with the date that Sestak announced his challenge.

Continuing this trend, Specter called for an exit strategy in Afghanistan just yesterday.

This chart couldn’t make the Specter example any clearer:

The obvious lesson here is that Democrats should mount aggressive primary challenges against Democrats who are getting in the way of healthcare reform, clean energy legislation, the employee free choice act and job-creating stimulus provisions. Defenders of the status quo will maintain that this tactic is more effective in places like Pennsylvania than it would be in places like Nebraska, Arkansas, Indiana or Louisiana, and they are probably right. But the way we deal with such Senators now doesn’t seem to be working very well, so I’d be more than willing to give this other strategy a shot.

By wide margins, Arkansas voters support the energy legislation about to be debated in the Senate. When asked about a bill that “limits pollution and greenhouse gas emissions through what’s been called a ‘Cap and Trade’ plan and also invests in clean, renewable energy sources”: 55% of voters support it and just 37% oppose it.

Here are the results:

All Voters: 55% Support and 37% Oppose
Democrats: 77% Support and 13% Oppose
Republicans: 39% Support and 54% Oppose
Independents: 47% Support and 44% Oppose
Rural Voters: 53% Support and 38% Oppose

Here is the results summary:

I hope Senator Lincoln is paying attention.