A new survey by the left-leaning Public Policy Polling shows Democratic Gov. Jay Nixon leading Dave Spence, his Republican challenger, by 19 points -- 54-35 percent.

PPP said the 19 points represented Nixon's largest lead since January.

From PPP's analysis:

"Nixon continues to be one of the more popular governors in the country with 54 percent of voters approving of him to 29 percent who disapprove.

"Spence continues to be widely unknown. (Some) 45 percent of voters don't have an opinion about him one way or another. Among those do, 25 percent see him favorably, while 30 percent have a negative view."

PPP said Nixon is winning among independent voters by 54-31 percent and is winning a higher-than-usual share of the GOP vote with 23 percent.

In other races:

* GOP incumbent Peter Kinder leads Democratic challenger Susan Montee by 42-38 percent. PPP said the race has "the greatest intrigue in state-level races this year."

* In the race for attorney general, Democratic incumbent Chris Koster has broken open the race and now leads Republican challenger Ed Martin 52-34 percent.