Question: Which U.S. Senator won re-election to a third term in which  James Charles Slattery was the Democratic candidate in 2008?

full_context: Document 1: United States presidential election, 2008: The United States presidential election of 2008 was the 56th quadrennial presidential election. It was held on Tuesday, November 4, 2008. Democratic Party nominees Barack Obama, a U.S. Senator from Illinois, and his running mate Joe Biden, a long-time U.S. Senator from Delaware, defeated Republican Party nominees John McCain, a long-time and current U.S. Senator from Arizona, and his running mate Sarah Palin, a Governor of Alaska. Obama became the first African American ever to be elected president of the United States, and Joe Biden became the first Roman Catholic ever elected vice president.
Document 2: David Boswell (Kentucky politician): David E. Boswell is a former Democratic member of the Kentucky Senate, having represented the 8th District from 1990 to 2011. Earlier he was a member of the Kentucky House of Representatives from 1978 through 1983. In 1983, he defeated Republican Richard Turner to be elected Agriculture Commissioner of Kentucky with 64%. In 1987, he was a candidate for Lieutenant Governor unsuccessfully in the Democratic Primary on a ticket paired with Grady Stumbo. The Stumbo-Boswell ticket came in fourth. He returned the political arena and was the 2008 Democratic nominee for U.S. Representative for Kentucky's 2nd Congressional District, and lost to Republican nominee Brett Guthrie. The congressional seat became open because of the retirement of Republican Ron Lewis.
Document 3: Electoral history of George McGovern: George McGovern, a Democratic Party politician from South Dakota, was first elected to the United States House of Representatives to represent South Dakota's 1st congressional district in 1956. He was re-elected in 1958, before making an unsuccessful run for the United States Senate in 1960 against Republican incumbent Karl Earl Mundt. After serving in the John F. Kennedy administration as director of the Food for Peace program, McGovern ran again for the Senate and narrowly prevailed over appointed Senator Joseph H. Bottum. In 1968, McGovern unsuccessfully sought the Democratic Party's presidential nomination at the Democratic National Convention and was re-elected to the Senate over former Governor of South Dakota Archie M. Gubbrud. In 1972, McGovern was successful in his campaign for the Democratic presidential nomination, but lost the election in a landslide to incumbent President Richard Nixon. McGovern was re-elected to the Senate in 1974 over Vietnam War veteran Leo K. Thorsness, but lost re-election in 1980 to then-U.S. Representative James Abdnor. McGovern made a final unsuccessful run for president in United States presidential election, 1984.
Document 4: United States Senate election in Alaska, 1984: The 1984 United States Senate election in Alaska was held on November 6, 1984. Incumbent Republican Senator Ted Stevens sought re-election to a third term in the United States Senate. Owing to his popularity and the conservative bent of Alaska, Stevens did not face major opposition, and easily crushed former Alaska Attorney General John Havelock in the general election.
Document 5: Dennis McKinney: Dennis McKinney (born July 24, 1960) is a former Kansas State Treasurer. He was a member of the Kansas House of Representatives where he represented the 116th House District for ten terms, the last six as the Democratic Party's leader (Minority Leader) in the Kansas House. In January 2017, he was a Democratic candidate for the party's nomination as the 4th District of Kansas nominee in the U.S. House of Representatives. At the Democrats' 4th District nominating convention February 10, 2017, he narrowly lost to James Thompson.
Document 6: United States Senate election in Kansas, 2008: The 2008 United States Senate election in Kansas was held on November 4, 2008. Incumbent Republican U.S. Senator Pat Roberts won re-election to a third term.
Document 7: Sam Brownback: Samuel Dale Brownback (born September 12, 1956) is an American politician and diplomat who is the 46th Governor of Kansas. A member of the Republican Party, Brownback was first elected to the U.S. House of Representatives during the Republican Revolution of 1994, representing Kansas's 2nd congressional district for a single term, before running in a 1996 special election for the U.S. Senate seat previously held by Bob Dole. He won the special election and the following two regular elections, serving until 2011. He ran for president in 2008, but withdrew before the primaries began and endorsed eventual Republican nominee John McCain. He was elected Governor of Kansas in 2010 and took office in January 2011.
Document 8: Jim Slattery: James Charles Slattery (born August 4, 1948) is an American politician. He served in the U.S. House of Representatives from 1983 to 1995 representing Kansas's 2nd congressional district as a Democrat, was the Democratic nominee for governor in 1994 and was the Democratic candidate for U.S. Senator in 2008.
Document 9: United States Senate election in Illinois, 1984: The 1984 United States Senate election in Illinois took place on November 6, 1984. Incumbent Republican Senator Charles H. Percy ran for re-election to a fourth term in the United States Senate. Senator Percy was opposed by Democratic nominee Paul Simon, who was a United States Congressman from Illinois's 22nd congressional district. The campaign between Percy and Simon was brutal and toughly-fought, and ended up with Simon ousting Percy by fewer than 90,000 votes, which was, at the time, considered an upset.
Document 10: Joe Biden presidential campaign, 1988: The 1988 presidential campaign of Joe Biden, the longtime Democratic United States Senator from Delaware and eventual 47th Vice President of the United States began on June 1987. He ran for President of the United States in the 1988 United States presidential election. He was considered one of the potentially strongest candidates in the field. However, in September 1987, newspaper stories stated he had plagiarized a speech by British politician Neil Kinnock. Other allegations of past law school plagiarism and exaggerating his academic record soon followed. Biden withdrew from the race later that month.
Document 11: United States elections, 2008: The governorship of 11 states and two U.S. territories were also up for election. Only one of them changed party hands: Democrat Jay Nixon won the Missouri gubernatorial election, replacing Republican Matt Blunt, who decided to retire instead of run for a second term.
Document 12: United States Senate election in Alaska, 2008: The 2008 United States Senate election in Alaska was held on November 4, 2008. Incumbent Republican U.S. Senator and former President pro tempore Ted Stevens ran for re-election to a seventh term in the United States Senate. It was one of the ten Senate races that U.S. Senator John Ensign of Nevada, the chairman of the National Republican Senatorial Committee, predicted as being most competitive. The primaries were held on Tuesday, August 26. Ted Stevens was challenged by Democratic candidate Mark Begich, the mayor of Anchorage.
Document 13: United States Senate election in Hawaii, 2004: The 2004 United States Senate election in Hawaii took place on November 2, 2004 alongside other elections to the United States Senate in other states as well as elections to the United States House of Representatives and various state and local elections. Incumbent Democrat U.S. Senator Daniel Inouye won re-election to an eighth term.
Document 14: United States Senate election in Kansas, 1998: The 1998 United States Senate election in Kansas was held November 3, 1998. Incumbent Republican U.S. Senator Sam Brownback won re-election to his first full term. Brownback was first elected in a special election held in 1996, when then-Senator Bob Dole resigned to campaign for U.S. President, after 27 years in the Senate. This would've been Dole's seventh term in office had he remained in his seat.
Document 15: J. James Exon: John James "Jim" Exon (August 9, 1921June 10, 2005) was an American Democratic politician. He served as the 33rd Governor of Nebraska from 1971 to 1979, and as a U.S. Senator from Nebraska from 1979 to 1997. Exon was a Nebraska Democrat who never lost an election, and the only Democrat to hold Nebraska's Class 2 U.S. Senate seat. He was elected and re-elected governor in 1970 and 1974, elected to the Senate in 1978, and re-elected in 1984 and 1990. He is the only Nebraskan besides George Norris, the architect of Nebraska's unicameral legislature, to win five consecutive statewide elections.
ground_truth: Pat Roberts