One month before voters cast their ballot in the Republican lieutenant governor primary, both incumbent Peter Kinder and challenger Brad Lager are taking to the airwaves in an attempt to claim the title of most conservative candidate.

Lager was first out of the gate, launching a pair of TV ads and a radio spot focusing how Kinder repaid the state $54,000 he spent for nights at St. Louis hotels while he attended events unrelated to his official office, such as baseball games and political rallies. Lager, a two-term state senator from Savannah, concludes that he's the "real conservative" candidate.

Kinder, who has served as lieutenant governor for eight years, responded this week with a 30-second ad of his own that criticizes Lager for voting to accept "almost $500 million in Obama stimulus funds into a bloated state budget." Kinder declares himself a “champion for conservative causes."

Last week, Kinder released a radio spot featuring the endorsement of conservative talker and fellow Cape Girardeau-native Rush Limbaugh.

The race has been contentious from the very start. Lager declared his candidacy Kinder was preparing to run for governor. Kinder pulled out of that race to seek re-election following a series of stories becoming public regarding his travel bills and relationship with a former stripper.

According to their April fundraising reports, both men had roughly $1.1 million in the bank. But two major GOP donors -- retired investor Rex Sinquefield and Joplin businessman David Humphreys -- recently donated a total of $600,000 to Lager's campaign. Both men were financial supporters of Kinder's as recently as last year.

Lager also recently received a $250,000 check from St. Joseph-based Herzog Contracting Corp.

Two other Republicans --Mike Carter of St. Charles and Charles Kullmann of St. Louis -- are also running in the lieutenant governor primary. There are eight Democrats running for their party's nomination.

Here are Lager's ads:

Here are Kinder's ads: