Before Adlai Stevenson losing to Dwight D. Eisenhower twice (1952 and 1956), losing presidential candidates often stayed politically active, or were consulted publicly as elder statesmen, or were asked to run for president again, a la Stevenson in 1956. Then the culture of America changed about the loser tag, and for the last 55 years, the losing major party candidates were considered toxic.
That is until John Kerry.Before getting to Kerry, let's look at losing candidates from 1976 on, not counting incumbent presidents who lost (Ford, Carter, Bush I) because a losing incumbent still gets a presidential museum. And six years must have passed since the election (so no 2008 or 2012 assessment yet).1984: Losing candidate = Walter MondaleBefore losing, Mondale served in the U.S. Senate from 1964-1976; U.S. Vice President from 1977-1981. Mondale got a plum 3-year job as US Ambassador to Japan but that doesn't count as an elected official nor as a significant poltical appointment.1988: Losing candidate = Michael DukakisBefore losing, Dukakis served as Governor of Massachusetts from 1975-1979 and from 1983-1990. After losing, Dukakis finished his term as governor and hasn't done anything political since.Dukakis did effect one major campaigning change--the two major candidates after convention run a "poltical sprint" to November. Dukakis with a 17-point lead in the polls took time off the campaign trail after convention to be Governor of Masschusetts.2000: Losing Electoral College Candidate = Al Gore(winning popular vote doesn't count)Before losing the Electoral College vote, Gore served in the U.S. House from 1977-1985, the U.S. senate from 1985-1993; and U.S. Vice President from 1993-2001.Gore has accomplished a lot since the 2000 election but nothing in the elected or significant appointee arena.2004: Losing candidate = John KerryBefore losing, Kerry served as Lt. Governor of Masschusetts (with Gov. Michael Dukakis) from 1983-1985; and the U.S. Senate from 1985 to current.After losing in 2004, Kerry not only finished the remainder of his 6-year term in the Senate, he was re-elected to another 6-year term in 2008 and became the chairman of the U.S. Senate Foreign Relations Committee.Kerry has wielded great influence on U.S. policy as a U.S. Senator and as a Chairman of an influential Senate committee.Now he has been nominated to replace Hillary Clinton as U.S. Secretary of State. His nomination to this high level Cabinet position is expected to be confirmed by the U.S. Senate.John Kerry has broken free from the stain as a major party presidential candidate loser and never lost stride influencing U.S. policy, and he continues to be consulted about political strategy.