"There's more of an emphasis on party ideology and partisan cohesiveness rather than trying to find common ground as Americans," Bayh told the Columbus (Ohio) Dispatch recently. "The bases of the parties are just alienated from each other. I've never seen the gap as large as today."
Republicans and Democrats alike "view one another in some ways as beyond adversaries, almost enemies," he said.
Yet soon after Bayh announced his retirement, Indiana's Rep. Brad Ellsworth announced he would run for the seat Bayh is abandoning after 12 years.
The Republican primary field Tuesday is more crowded with some well-known names in Indiana politics: former Rep. John Hostettler, state Sen. Marlin Stuzman and former U.S. Sen. Dan Coats, who unretired to run for the seat.
President Barack Obama won Indiana with 50 percent of the vote in 2008 over Republican presidential candidate John McCain's 49 percent.
Soon after Bayh announced his retirement, the non-partisan CQ Politics and Cook Political Report changed their race rating from "Leans Democratic" to "Leans Republican." And a Rasmussen poll conducted in mid-April support the change in designation.
In competitive primaries across the United States, Republicans are trying to prove they are the most conservative candidates, Real Clear Politics reported. In Indiana, Coats, Hostettler and Stutzman battled to wear the conservative mantle going into the primary. Coats was recruited by the national party and is considered the favorite, but all three have led Ellsworth in general election polling.
Polls indicate the eventual Republican nominee will be favored to win on Election Day. Before President Obama's victory in 2008, Indiana went red in all but three presidential elections dating back to 1928.
In Indiana's 5th congressional district Republican incumbent Dan Burton is seen by some observers as vulnerable to a primary challenge. One-time Republican candidate Brose McVey, Indiana Republican Party Executive Director Luke Messer, state Rep. Mike Murphy and 2008 primary challenger John McGoff have all announced their intentions to challenge Burton, as has Andy Lyon, a Tea Party activist who says he's a strict constructionist.
With Ellsworth looking to move to the Senate, his House seat is considered extremely competitive.
Indiana's 8th congressional district: The Republican nominee will be decided from a crowded eight-person field while the Democratic party leadership named state Rep. Trent Van Haaften.
Multiple candidates from both parties also are lining up to succeed Republican Rep. Steve Buyer, who also announced his retirement in 2010.
Notable deaths of 2014 [PHOTOS]