If Tom Kean, Jr. wins his race for the United States Senate, Republicans in the 21st district would meet next January to fill his seat in the State Senate. Union County insiders say that Assemblyman Jon Bramnick would be the strong favorite to win that contest over his Assembly colleague, Eric Munoz. That would mean another Special Election Convention to fill the open Assembly seat, and party leaders say the favorite for that would be Union County GOP Chairman Philip Morin, a former Mayor of Cranford. Morin, party leaders say, would not run again for County Chairman if he wins election to the Legislature. The last time the 21st district had two Special Election Conventions was in early 2003, when State Senator Richard Bagger resigned after just a year in office to devote more time to his position with Pfizer, the pharmaceutical manufacturer. Kean, then an Assemblyman, ran unopposed for the Senate seat; six Republicans then sought Kean’s Assembly seat. The contest, which attracted candidates from Essex, Morris and Somerset counties, was settled by a caucus of Union County Republicans, who picked Bramnick over Morin by just three votes on the second ballot.