Both Meg Whitman (E-Bay) and Carly Fiorina (HP) are entering U.S. politics in California where anything is possible. Both were high tech corridor heavyweights managing two of the largest ICT corporations in the world. Ross Perot (EDS) tried to run for President - twice. Some considered his chances weak in the beginning, yet he almost pulled it off, some analyst suggest. Former Vice President Cheney while CEO of Halliburton between 1995 and 2000, has always been in politics starting in 1969 until his retirement last year.
U.S. Governments generally elect career politicians, rising through the ranks from town councils, state legislatures and finally federal institutions. Many have careers spanning 40+ years. Congressman John Dingell of Michigan has served in office since 1955 and is the longest serving elected House member in history.
There are two other sources of diplomats. One is not too far distant from the political spectrum, the other is. The first is the military, Gen Eisenhower (President) , Gen Colin Powell (Secretary of State), and several generals since the civil war went into politics at various levels. One of the surprises in the 20th century was General Douglas MacArthur's decision not to enter politics despite many who felt he would have won a Presidential race in 1952. Theodore Roosevelt has the distinction of serving first in politics, leaving to enter the military (1898 Spanish-American War) and reenter politics eventually becoming the 26th U.S. President from 1901 to 1909.
The other source is actors such as former President Regan, Fred Thompson (Senator), Clint Eastwood (Mayor), Arnold Schwarzenegger (Gov of California) and many others. The track records of each are likely to be debated forever.
The corporate world has not had significant leadership roles in recent U.S. elections. The question often arises as to why. The answers vary from scrutiny, pay, and general consensus; it's easier to influence change from outside the political arena than from within. Should be an interesting news cycle watching Meg Whitman and Carly Fiorina's attempts getting elected in California. Silicon Valley may not be the safe haven they think it is. Fiorina is challenging three-term Senator Barbara Boxer (who's been in federal politics since 1983) while Whitman is going up against the Terminator who's been Governor since 2003.