Question: Who lost against U.S. Senator Pat Roberts in his re-election to a third term?

Context paragraphs:
Milton R. Wolf: Milton R. Wolf (born 1971) is an American physician.  He is a Tea Party movement-aligned activist who ran against incumbent Kansas U.S. Senator Pat Roberts for the Republican Party nomination in the 2014 United States Senate election.  On August 5, 2014, Wolf was defeated by Roberts, but held him under fifty percent.  The final percentages were Roberts 48% and Wolf 41%.

United States Senate election in Kansas, 1996: The 1996 United States Senate election in Kansas was held November 5, 1996.  Incumbent Republican U.S. Senator Nancy Kassebaum decided to retire instead of seeking a fourth term.  Republican Pat Roberts won the open seat.

United States Senate election in Kansas, 2002: The 2002 United States Senate election in Kansas was held on November 4, 2002.  Incumbent Republican U.S. Senator Pat Roberts won re-election to a second term easily because no Democrat filed to run.

Joseph W. Cowgill: Joseph William Cowgill (April 24, 1908 – November 19, 1986) was an American Democratic Party politician who served as the Minority Leader of the New Jersey State Senate.  He is a 1929 graduate of the University of Pennsylvania and a 1933 graduate of the University of Pennsylvania Law School.  He was elected to the New Jersey General Assembly representing Camden County in 1940.  He did not seek re-election to a second term in 1941, but instead ran for Camden County Surrogate (Probate Court Judge).  He resigned as Surrogate in 1943 to join the U.S. Navy during World War II.  Cowgill was an Assistant Camden County Prosecutor in 1945, and served as the Camden County Counsel from 1947 to 1953, and again from 1957 to 1960.  He was a Delegate to the 1947 New Jersey Constitutional Convention, and an Alternate Delegate to the 1956 Democratic National Convention.  He was elected to the Camden County Board of Chosen Freeholders in 1952; he did not seek re-election in 1955, but instead ran for an open State Senate seat when Bruce A. Wallace retired.  In a close race, Cowgill defeated Republican Haddon Township Mayor William G. Rohrer by 290 votes, 54,683 (50.02%) to 54,393 (49.76%).  Cowgill again faced Rohrer when he sought re-election in 1959; this time, Cowgill won by 4,092 votes, 61,656 (51.72%) to 57,564 (48.28%).  He served as the Senate Minority Leader from 1959 to 1964.  In 1963, Cowgill was defeated for re-election to a third term as State Senator, losing to Republican Frederick Scholz by 13,627 votes, 72,873 (54.94%) to 59,246 (44.66%).

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.

United States Senate election in Minnesota, 2002: The 2002 United States Senate election in Minnesota took place on November 5, 2002.  Incumbent Democratic U.S. Senator Paul Wellstone was running for re-election to a third term, but died in a plane crash eleven days before the election.  The Democratic-Farmer-Labor Party (DFL) chose former Vice President and 1984 Presidential candidate Walter Mondale to replace Wellstone on the ballot.  Mondale lost to Republican Mayor of Saint Paul Norm Coleman.  The day before the election, Independence Governor Jesse Ventura had appointed Dean Barkley (IP) to serve the rest of Wellstone's term.  As of 2017, this is the last Senate election in Minnesota won by a Republican.

Greg Orman: Gregory John "Greg" Orman (born December 2, 1968) is an American entrepreneur.  He ran as an independent to represent Kansas in the United States Senate in the 2014 election, and lost to the incumbent Senator Pat Roberts.

United States Senate election in Washington, 1988: The 1988 United States Senate election in Washington was held on November 8, 1988.  Incumbent Republican U.S. Senator Daniel J. Evans decided to retire instead of running for re-election to a full term, after being appointed to the seat in 1983, and won re-election to a partial term that same year.  Republican former U.S. Senator Slade Gorton, who had just lost a re-election bid in 1986, won the open seat.

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.

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.

Supporting paragraphs: Jim Slattery United States Senate election in Kansas, 2008
Answer: James Charles Slattery