As well they should, but I wouldn't get too excited about one result from a sample size of 402 with a margin of error of +/- 5%.*
If it turns out to signal a reversal of the recent trending in Ron Johnson's favor, then excitement would be appropriately in order.
As more voters begin to pay attention to the election they should justifiably be inclined to perceive Ron Johnson as a double-talking charlatan, something a few of us noticed as far back as May when the Fox News candidate, having just recently dismounted a Tea Party podium where he'd been shouting about evil liberals clamping down on free speech, ungraciously tore down the campaign posters of his Republican primary rivals from the wall at the WISGOP convention.
Here's one such elector.
* Several of the so-called national pundits have already written Senator Feingold off, but I wouldn't trust any of them either.