The latest national presidential poll shows Jeb Bush and Scott Walker continuing to slide as outsiders Donald Trump and Ben Carson hold strong at the top.

The survey, out today from Monmouth University, has Trump leading the pack with 30 percent of the vote and Carson following in second place with 18 percent. That’s a whopping 13 percent increase for Carson over last month’s poll. (The poll only surveyed 366 voters, so take it for what it’s worth.)

They’re followed by Jeb Bush, who’s in third place with eight percent, down four points from August.

Even more striking, however, is Scott Walker’s decline to three percent from 11 percent in August, and to seventh place today from third place in August.

Here’s how, according to Monmouth, candidate support has varied over the past few months:

So, what does a guy like Scott Walker do? Well, his super PAC is out today with its first ad, “Fight & Win,” which showcases the conservative reforms he implemented in Wisconsin, including of course his victory over the state’s public-sector unions. It presents him as somebody who “never backs down” and “takes decisive action.”

The goal, a source at the PAC tells me, is to refocus the conversation on Walker’s conservative record in Wisconsin. The super PAC and the Walker campaign aren’t allowed to communicate, but the Walker campaign has of course been pulled into all sorts of conversations — about birthright citizenship, building a wall on the Canadian border, Republican leadership in Washington, D.C. — all of which have taken him away from the Wisconsin story that made him so popular. The Walker PAC will be running ads from now through the Iowa caucuses, so expect more ads like this one in the weeks and months to come.

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