QUESTION: What do former President Richard Nixon, former President Jimmy Carter, former President Ronald Reagan, Rudy Giuliani, Mitt Romney, Fred Thompson and John Edwards all have in common?

ANSWER: They were all basically unemployed when they sought the presidency.

Not having a full-time demanding job is a decided advantage when running for president. You have plenty of time to devote to your campaign.

Richard Nixon had all the time in the world to devote to politics after leaving the vice presidency in 1961 when he was elected president in 1968.

Carter had served as governor of Georgia but was no longer in office when he won the presidency in 1976. Ronald Reagan had served two terms as governor of California but likewise was out of office when he was elected president in 1980.

All of the top three current contenders for the Republican nomination – Giuliani, Romney and Thompson – don’t currently have regular full-time jobs. Giuliani is a former Mayor of New York and is involved in several ventures including a law firm but basically his time is his own. Romney served as governor of Massachusetts but is no longer in office and Thompson has been a part-time actor since leaving the U.S. Senate.

Add to this list other successful candidates who held jobs that were not overly demanding: Bill Clinton, George H.W. Bush and George W. Bush. Clinton and George W. Bush were governors of their states. Clinton had been governor of Arkansas for a long-time when he was elected in 1992 and the job was fairly routine by then. George W. Bush was governor of Texas -- a job which in reality had little power-- when he was elected in 2000.

George H.W. Bush was the incumbent vice president when he won in 1988 and had great leeway to set his own schedule for a job with little responsibility.

Thus it should come as no great surprise that no sitting member of the United States Senate has been elected president since John F. Kennedy in 1960. Senators have very demanding schedules and they face the addition issue of actually having to cast public votes on very controversial issues during the course of the campaign.

Of course, this year could be the exception that proves the rule. Two of the leading Democratic contenders -- Hillary Clinton and Barrack Obama -- serve in the Senate. Other lesser Democratic candidates -- Chris Dodd and Joe Biden -- also are incumbent senators.

On the Republican side, John McCain is a highly visible member of the Senate and the leading role he played during the recent Senate consideration of the controversial immigration reform legislation is one of the factors that has put his campaign into a tailspin.

Being an incumbent U.S. senator is not all bad when running for president. Incumbent senators can raise money from individuals and political action committees that will have to continue to deal with them even if they lose the nomination.

Also, Hillary Clinton was able to transfer a significant amount of left over campaign funds from her Senate campaign committee account following her successful re-election campaign last year. Presidential candidates are free to transfer funds from their regular federal re-election accounts whereas state officials like governors cannot transfer funds from their state election accounts to their federal presidential campaign.

Incumbent senators have won their party’s nomination since 1960 (examples include George McGovern in 1972, Bob Dole in 1996 and John Kerry in 2004) but they were not able to win the grand prize. Dole, in fact, chose to step down from his role as Senate Majority Leader midway through his campaign. He simply could not hold that demanding position and run for president.

It is a quirk in our electoral system that holding high level national office (except for the non-taxing job of vice president) often is a disqualifier for seeking the top office in the land. That’s not the way it works in many western countries with parliamentary systems which virtually require a successful candidate for prime minister or chancellor to already be a national leader.

That could explain why in recent years we have elected some presidents with very little foreign policy experience. Being governor of a state does not guarantee that you know the first thing about how to conduct foreign policy in an increasingly complicated world. Bill Clinton had difficulties with foreign policy early in his tenure and George W. Bush clearly has had his problems with the rest of the world.

Senators do deal with foreign policy on a regular basis. Maybe electing someone with a demanding job like being a U.S. senator is not such a bad idea after all.

Respond to the Writer

Martin Frost served in Congress from 1979 to 2005, representing a diverse district in the Dallas-Ft. Worth area. He served two terms as chairman of the House Democratic Caucus, the third-ranking leadership position for House Democrats, and two terms as chairman of the Democratic Congressional Campaign Committee. Frost serves as a regular contributor to FOX News Channel and is a partner at the law firm of Polsinelli, Shalton, Flanigan and Suelthaus. He holds a Bachelor of Journalism degree from the University of Missouri and a law degree from the Georgetown Law Center.