Question: When did the senator who vacated a U.S. Senate seat which Thomas M. Davis considering a run for in 2008 serve as Secretary of the Navy?

<P0-S0> John William Warner (born February 18, 1927) served as Secretary of the Navy from 1972 to 1974 and as a five-term Republican United States Senator from Virginia from January 2, 1979, to January 3, 2009. <P0-S1>  He did not seek reelection in 2008. <P0-S2>  He works for the law firm of Hogan Lovells, where he had previously worked before joining the United States Department of Defense. <SEP> <P1-S0> Thomas Milburn "Tom" Davis III (born January 5, 1949) is a former Republican member of the United States House of Representatives, representing Virginia's 11th congressional district in Northern Virginia, and currently serves as the Rector and Professor at George Mason University. <P1-S1>  Davis was considering a run for the U.S. Senate seat being vacated by five-term incumbent and fellow Republican John Warner in the 2008 election, but decided against it. <P1-S2>  He announced on January 30, 2008, that he would not seek reelection to an eighth term. <P1-S3>  Davis resigned from Congress on November 24, 2008. <SEP> <P2-S0> The 2006 United States Senate election in New Jersey was held on November 7, 2006. <P2-S1>  Incumbent Democratic U.S. Senator Bob Menendez was elected to represent New Jersey in the United States Senate for a six-year term which ended in January 2013. <P2-S2>  The seat was previously held by Democratic Governor of New Jersey Jon Corzine. <P2-S3>  After he stepped down from his Senate seat and was sworn in Governor, Corzine appointed Rep. Menendez, who was sworn in on January 18, 2006. <P2-S4>  Menendez was challenged by Republican Thomas Kean, Jr. and seven other candidates. <P2-S5>  Filing for the primary closed on April 10, 2006. <P2-S6>  The primary election was held on June 6, 2006. <P2-S7>  Menendez became the first Hispanic to hold a U.S. Senate seat from New Jersey, and was the first Latino elected to statewide office in the state. <SEP> <P3-S0> Lula Johnson Davis was Secretary for the Majority of the United States Senate from 2008 to 2011. <P3-S1>  Davis was born in Louisiana. <P3-S2>  She received a B.S. in office administration and an M.Ed., in guidance counseling from Southern University in Baton Rouge, Louisiana. <P3-S3>  She began her career with the Senate as a legislative correspondent for Senator Russell B. Long of Louisiana. <P3-S4>  After Senator Long retired from the Senate in January 1987, Davis worked as an office assistant for the Democratic Policy Committee’s Senate floor staff office. <P3-S5>  In 1993, she became a member of the Democratic floor staff. <P3-S6>  In 1995, she was promoted to chief floor assistant. <P3-S7>  In 1997, she assumed the position of assistant secretary. <P3-S8>  After the retirement of Martin P. Paone, in January 2008, the Senate elected Davis Secretary for the Majority. <P3-S9>  As Secretary for the Majority, she was a senior procedural advisor to the Senate Majority Leader, Senator Harry Reid, and supervised the day-to-day Senate schedule. <P3-S10>  In so doing, she often worked with Secretary for the Minority David J. Schiappa. <P3-S11>  Davis told Senators what they could and could not do when it came to rules and procedure. <P3-S12>  Consequently, Davis was called “one of the most powerful unelected people in the U.S. Senate.” <P3-S13>  Davis retired at the end of the 111th Congress.