Get ready for a knock-down, drag-out eighteen month marathon between Republican Assemblymen Steve Corodemus and Sean Kean, who both want the soon-to-be open 11th district State Senate seat of Joseph Palaia. The two survived a costly and well-run challenge last week against Democrats Matt Doherty and James Reilly. Kean was the top vote-getter, finishing 435 votes ahead of Corodemus. But Kean enjoyed labor endorsements that Corodemus did not have, and Democrats were more aggressive in their attacks on Corodemus. The two Republicans don’t like each other and neither will be likely to defer to the other on the Senate seat. Monmouth County Republicans now award their organization line at an open convention, although party leaders could punt — as they did in the gubernatorial primary — and not choose between the two Assemblymen. That could mean as many as two open Assembly seats in the next election.