Question:  The 1996 United States Senate election in Georgia was the first election after the retirement of the current co-chair of what organization?

Context paragraphs:
United States Senate election in Alaska, 1996: The 1996 United States Senate election in Alaska was held on November 5, 1996.  Incumbent Republican United States Senator Ted Stevens ran for re-election to a fifth term in the United States Senate.  Stevens faced off against Democratic nominee Theresa Obermeyer, a former member of the Anchorage School Board, and Green Party nominee Jed Whittaker, a commercial fisherman.

United States Senate election in Iowa, 1996: The 1996 United States Senate election in Iowa was held on November 5, 1996.  Incumbent Democratic United States Senator Tom Harkin sought re-election to a third term in the United States Senate, and he was challenged by United States Congressman Jim Ross Lightfoot from Iowa's 3rd congressional district.  Lightfoot had won the Republican primary against two opponents, while Harkin had won his primary uncontested, so both moved on to the general election, where they engaged in a toughly-fought campaign.  Ultimately, Harkin was successful in his bid, and defeated Lightfoot, albeit by the thinnest margin of his career.

United States Senate election in Georgia, 1996: The 1996 United States Senate election in Georgia was held on November 5, 1996.  Incumbent Democratic United States Senator Sam Nunn decided to retire instead of seeking a fifth term.  The Republican Party nominated Guy Millner, a multi-millionaire businessman who was also the unsuccessful candidate that ran against Zell Miller in the 1994 gubernatorial election.  Millner emerged as the victor from a crowded 6-person primary in July 1996.  However, Max Cleland, the Secretary of State of Georgia ran unopposed in the Democratic primary.

United States Senate election in Illinois, 1996: The 1996 United States Senate election in Illinois took place on November 5, 1996.  Incumbent Democratic United States Senator Paul Simon opted to retire rather than seek a third term in the United States Senate.  In the Democratic primary, United States Congressman Dick Durbin emerged victorious, while State Representative Al Salvi won the Republican primary.  Though the election was initially anticipated to be close, Durbin ended up defeating Salvi by a comfortable double-digit margin of victory, allowing him to win what would be the first of several terms in the Senate.

United States Senate election in Oregon, 1996: The 1996 United States Senate election in Oregon was held on November 5, 1996.  Incumbent Republican United States Senator Mark Hatfield decided to retire after thirty years in the Senate.  Oregon State Senate President Gordon H. Smith, who had run for the Senate earlier that year, won the Republican primary, while businessman Tom Bruggere won a contested Democratic primary.  The contest between Smith and Bruggere was one of the toughest that year, but ultimately, Smith was able to keep the seat in the Republican column and defeated Bruggere by a narrow margin.

United States Senate election in Indiana, 2010: The 2010 United States Senate election in Indiana took place on November 2, 2010, alongside 33 other elections to the United States Senate in other states and elections to the United States House of Representatives and various state and local elections to fill Indiana's class III United States Senate seat.  Incumbent Democratic U.S. Senator Evan Bayh decided in February 2010 to retire instead of seeking a third term shortly after former U.S. Senator Dan Coats announced his candidacy for Bayh's contested seat.  No Democratic candidate submitted enough signatures by the deadline to run, leading Democratic officials to choose U.S. Congressman Brad Ellsworth to be the nominee.  The Libertarian Party nominated YMCA instructor Rebecca Sink-Burris, who had previously run against Evan Bayh in the United States Senate election in Indiana, 1998 but with less success than in this election.  Republican nominee and former U.S. Senator Dan Coats won the open seat.

United States Senate election in Montana, 1996: The 1996 United States Senate election in Montana took place on November 5, 1996.  Incumbent United States Senator Max Baucus, who was first elected in 1978 and was re-elected in 1984 and 1990, ran for re-election.  He was unopposed in the Democratic primary, and moved on to the general election, where he faced a stiff challenge in Denny Rehberg, the Lieutenant Governor of Montana and the Republican nominee.  Despite Bob Dole's victory over Bill Clinton and Ross Perot in the state that year in the presidential election, Baucus managed to narrowly win re-election over Rehberg to secure a fourth term in the Senate.

United States Senate election in Maine, 1996: The 1996 United States Senate election in Maine was held November 5, 1996.  Incumbent Republican United States Senator William Cohen decided to retire instead of seeking a fourth term.  To replace him, United States Congressman and former Governor of Maine Joseph E. Brennan won the Democratic primary while political consultant and 1994 nominee for Governor of Maine Susan Collins won the Republican primary.  A competitive general election ensued, but Collins ultimately won out over Brennan, keeping the seat in the Republican column.  With Collins' election to the Senate in 1996, Maine became only the second state after California to have two sitting women senators.

Sam Nunn: Samuel Augustus Nunn Jr. (born September 8, 1938) is an American lawyer and politician.  Currently the co-chairman of the Nuclear Threat Initiative (NTI), a charitable organization working to prevent catastrophic attacks with nuclear, biological and chemical weapons, Nunn served for 24 years as a United States Senator from Georgia (1972 until 1997) as a member of the Democratic Party.  His political experience and credentials on national defense reportedly made him a potential running mate for Democratic presidential candidates John Kerry (2004) and Barack Obama (2008).

United States Senate election in Montana, 1928: The 1928 United States Senate election in Montana took place on November 6, 1928.  Incumbent United States Senator Burton K. Wheeler, who was first elected to the Senate in 1922, ran for re-election.  After successfully defeating several challengers in the Democratic primary, Wheeler advanced to the general election, where he faced Republican nominee Joseph M. Dixon, the former Governor of Montana who had previously served in the United States Senate from 1907 to 1913.  Though the election was closer than Wheeler's first election, he still managed to defeat Dixon to win his second term in the Senate.

Supporting paragraphs: United States Senate election in Georgia, 1996 Sam Nunn
Answer: Nuclear Threat Initiative