TOPEKA — Some prominent Kansas Democrats expect their party’s presumed nominee for governor to emerge by Labor Day for an underdog’s challenge to Republican incumbent Sam Brownback.

The most-often mentioned names of potential Democratic candidates in recent weeks are Kansas House Minority Leader Paul Davis, of Lawrence; businesswoman and former Board of Regents member Jill Docking, of Wichita, and former state Agriculture Secretary Joshua Svaty, an Ellsworth County native.

Brownback hasn’t formally kicked off his 2014 re-election campaign, but he’s raising money for it. As the Republican incumbent in a GOP-leaning state, he enjoys a built-in advantage, even with persistent criticism from Democrats and disaffected moderate Republicans.

The conservative governor’s push for aggressive personal income tax cuts is likely to be a key issue, with critics arguing that the reductions favor the wealthy and will starve public schools and vital state programs. Legislators also are expecting a Kansas Supreme Court ruling early next year in a lawsuit seeking to force the state to boost spending on public schools, and some liberal Democrats see Brownback as vulnerable on social issues, including abortion.

But Democrats acknowledge that their top candidate will need to raise hundreds of thousands of dollars and build statewide name recognition early. In 2010, the Democratic nominee, state Sen. Tom Holland, of Baldwin City, was hampered by a relatively late start in February of that year.

“I think there’s an opportunity to get a quicker start to the campaign than what happened four years ago,” said Senate Minority Leader Anthony Hensley, a Topeka Democrat. “I’m anticipating, very likely before Labor Day, there will be announcements.”

Brownback and his allies believe that his tax cuts not only will bring widespread relief to taxpayers but also stimulate the economy. His conservative stances on issues such as abortion resonate with the GOP’s base, and Republicans outnumber Democrats by about 344,000 among the state’s nearly 1.8 million registered voters.

The governor began the year with more than $518,000 in campaign funds, and Democrats concede that he’s likely to have plenty of money for a re-election bid. Brownback raised almost $3.1 million for his successful 2010 campaign, almost half of it in 2009.

Also, Republicans at all levels are likely to tap opposition to President Barack Obama, a Democrat. Kansas hasn’t been carried by a Democratic presidential candidate since Lyndon Johnson in 1964, and a wave of anti-Obama sentiment in 2010 helped sweep Brownback into the governor’s office.

“We just don’t sense that he’s vulnerable,” said Clay Barker, executive director of the Kansas Republican Party. “The Democrats have no natural leader whose name is well-known and who has a lot of money.”

Svaty, 33, is a vice president for the Salina-based Land Institute, which promotes sustainable agriculture. He served in the Kansas House for more than six years before his stint as the state’s appointed agriculture secretary from 2009 to 2011. Afterward, Svaty was an adviser to the Environmental Protection Agency’s regional administrator in Kansas City, Mo. He did not return a telephone message seeking comment about his plans.

Davis, a 41-year-old attorney, has served in the House since 2003, and he’d have to give up his seat to run for governor. He’s been a leading critic of Brownback’s administration, and there’s been speculation for months that he’ll run. But he’s not said publicly whether he’s considering the race.

“Kansans deserve the opportunity to choose a new direction for our state in the next election, and I am certain that a competitive opponent against Sam Brownback will emerge in the coming months,” Davis said in a statement last week.

Docking is a 57-year-old investment adviser who served on the Board of Regents from 2007 to 2010. In 1996, she was Brownback’s Democratic opponent for the U.S. Senate, garnering 43 percent of the vote to Brownback’s 54 percent. Her husband, Tom, is a former lieutenant governor and the son and grandson of Kansas governors.

She declined to comment about a run for governor, saying she’s not sure what her future holds. She has a blog that features criticism of Brownback.

“I am committed to helping to turn the political climate in Kansas around,” she said.