Paul Rand CPAC 2013
Senator Rand Paul of Kentucky speaks at the Conservative Political Action Conference (CPAC) at National Harbor, Maryland March 14, 2013. Reuters

Rand Paul and Marco Rubio might be considered future GOP presidential possibilities, but are they tall enough for the job?

Not if American history serves as any guide.

Conservative columnist and gadfly Ann Coulter raised the issue of the height of U.S. political candidates to Fox's Sean Hannity last month when she suggested that prominent Republicans like Kentucky senator Paul and Florida senator Rubio might be too short to ever be elected president. “Rubio and Paul are as tall as my iPod,” Coulter told Fox News' Sean Hannity last month. “You can’t run a short candidate.”

Insults aside, height -- of lack thereof -- could be an obstacle for Rubio, who is listed at about 5-foot-9, and Paul, who measures 5-foot-8. At the highest level of U.S. politics, being short appears to be a distinct disadvantage -- and it has been since long before the age of television.

According to the 1982 book by psychologist John Gillis called “Too Small, Too Tall,” the taller candidate has won 80 percent of the elections in the 20th century.

Of course, there have been a few exceptions. Reportedly, during the 1976 election between Jimmy Carter (5-foot-9) and the incumbent Gerald Ford (6-foot-1), Carter’s aides stopped at nothing to prevent their man from being photographed next to his opponent. (Carter won the election).

In elections since 1984, the favoritism toward height isn't quite so pronounced.

In the nine presidential elections since 1976, the taller candidate has won five times, the shorter, four times. (In the 1992 election between Bill Clinton and George H. W. Bush, both men were exactly 6-foot-2).

In the 1988 election between Bush and Michael Dukakis, the height difference was a staggering six inches (Bush easily won). However, Bush’s son, George W. Bush (6-foot-0), won twice against taller challengers Al Gore (6-foot-2) and John Kerry (6-foot-4). Kerry, in fact, was four and a half inches taller than his opponent (and still lost).

Barack Obama (6-foot-1) was much taller than the man he defeated in 2008, John McCain (5-foot-9). Obama then reversed historical trends by beating Republican challenger Mitt Romney (6-foot-2) in 2012.

American voters seem to place a greater emphasis on a politician’s height – much moreso than continental Europeans, where short men such as Nicolas Sarkozy (5-foot-6), Silvio Berlusconi (5-foot-5), Francois Hollande (5-foot-7),Vladimir Putin (5-foot-6) and Dmitri Medvedev (5-foot-4) have had no trouble reaching the pinnacle of political power.

Nic Fleming wrote in the Guardian newspaper: “Voters see tall politicians as better suited for leadership, according to a survey of how people visualize their leaders. Psychologists believe the bias may stem from an evolved preference for physically imposing chiefs who could dominate enemies.”

Perhaps in the U.S. tallness is associated with the 19th century pioneer and cowboy spirit that was based on physical strength and domination as well as self-reliance.

The situation for female heads of state is entirely different. Women are, on average, shorter than men and they are still battling men for equality in the sphere of politics. German Chancellor Angela Merkel (perhaps the most powerful woman on earth) is 5-foot-5, about average for the fairer sex; Australia’s Julia Gillard and Argentina’s Cristina Fernandez de Kirchner are roughly the same height as Merkel.

But while female political chiefs, especially in the Western world, likely do not have to worry about height, they must contend with prejudices about beauty and age more than their male counterparts.