The leader of Kansas' moderate Republicans said three weeks of attack ads from conservative groups, including those with ties to the Koch brothers, are to blame for Kansas Senate moderates' losses during Tuesday's primary.

Senate President Steve Morris (R-Hugoton), who lost his own seat to state Rep. Larry Powell in the primary, confirmed that internal polls showed moderate Republicans in the lead until roughly three weeks ago when a series of conservative groups launched radio and television attack ads on moderates, tying them to President Barack Obama and claiming they supported Obamacare. Seventeen out of 22 moderate Republican Senate candidates were defeated Tuesday, a culmination of a bitter GOP war that has engulfed the state since 2011.

"They tried to tie our folks to President Obama even though we had nothing to do with him," Morris told HuffPost. "They said we all supported Obamacare and that's not true. It's effective. The campaigns we did were positive and informational. The campaigns against us were very nasty. Evidently negative campaigning must work."