Sam Brownback is one of the most unpopular Governors in the country. Only 37% of Kansas voters approve of him to 52% who disapprove. He meets with near universal disapproval from independents (22/66) and Democrats (14/81), but what really drives his numbers down is that even among Republicans just 55% approve of him to 30% who disapprove. Brownback's signature proposal for phasing out the income tax may be part of what's bringing him down. Just 37% of voters support it with 48% in opposition.
Generally a Governor with Brownback's approval numbers would be trailing for reelection. But Republicans have a more than 20 point party identification advantage in the state, and Democrats don't have a particularly long bench. The one Kansas Democrat who is universally well known- former Governor Kathleen Sebelius- has seen her popularity decline as a result of serving in the Obama administration. 44% of voters in the state see her favorably to 47% with a negative opinion.
We looked at 5 other Democrats besides Sebelius but none of them has more than 32% name recognition- Wichita Mayor Carl Brewer and former Governor Mark Parkinson are both at 32%, Kansas City Mayor Joe Reardon is at 28%, 2010 nominee Tom Holland is at 27%, and Shawnee County DA Chad Taylor is at 20%.
So despite his unpopularity, the Republican lean of the state and the low profile of the Democrats we tested still allows Brownback to lead every potential match up we looked at. He's up 4 points on Brewer at 44/40, 5 on Sebelius at 48/43, 6 on Parkinson at 45/39, 7 on Holland at 45/38, 9 on Reardon at 45/36, and 10 on Taylor at 44/34.
Full results here