There was a movie made in the late 1960s/early 1970s where a character says "If you want to have a perfect president, take a boy at the age of 12 (hey it was the guilded age of sexism) and teach him for the next 23 years everything he needs to know"
To some extent, its true. As far as experience yielding the best results --- we have a mixed bag. The most common experience patterns are General, Governor, and Vice President --- all poorly suited to legislative success. The best choice for legislative success --- service in Congress ---- was more or less non-existent for the three decades prior to 2009 and not for the better. And prior to World War II, other than Warren Harding and William McKinley, no President had Congressional experience in the first half of the 20th Century.
Dwight Eisenhower was a military Commanders like 7 other presidents. Some great or near great (Washington and Jackson) others like Pierce and Grant horrible...the rest is a mixed bag or non-issues (Wm Henry Harrison and Garfield).
There is Governors and 19 Presidents have held that office....but what of it. Of the 13 states with a Strong or Very Strong Governor system, we have had 6 presidents from states (Coolidge-MA, Teddy Roosevelt, FDR, Cleveland and van Buren - NY, Clinton-AR and Wilson-NJ). [BTW - Strong Governor systems have extensive appointment and removal power, veto power, including line item veto, control of the Budget process and significant influence over legislative agenda, and office tenure (ie term limits).] The rest have come from more middling states (power-wise) and one of course came from the epitome of weak governor states, Texas and GW Bush.
The Vice Presidency is arguably the worst training ground and one's success in the Vice-Presidency is measured by success in the presidency. Of our 14 former VPs becoming President, only five got there without presidential funeral attendance (Adams, Jefferson, Van Buren, Nixon and GHW Bush). During the same period, we had 13 Vice presidents
Of course Cabinet Secretaries and Ambassadors have also run and achieved the White House ---- but again its a mixed bag....for every Monroe, you get a Hoover.
Since World War II, we've had 12 Presidents (Truman, Eisenhower, Kennedy, Johnson, Nixon, Ford, Carter, Reagan, GHW Bush, Clinton, GW Bush, and Obama) , 7 have served in Congress (Truman, Kennedy, Johnson, Nixon, Ford, GHW Bush, and Obama). Since 1976, we have had six Presidents, four of whom had no Congressional experience at all and if you throw in GHW Bush, who served two terms in the minority in the 1960s roughly 20 years before being elected President, five of whom with nothing more than a rudimentary idea how Congress works and how to get a legislative agenda passed.
Curiously of the 13 Vice Presidents during the same period (Barkley, Nixon, Johnson, Humphrey, Agnew, Ford, Rockefeller, Mondale, GHW Bush, Quayle, Gore, Cheney, and Biden), 11 have had Congressional experience. In fact, two Senate majority leaders have been VP (Barkley and Johnson). Quayle, Biden and Gore, despite not being Senate floor leaders, managed legislation on the floor of the Senate. You might argue to exclude both GHW Bush and Cheney from this list. Bush I served 2 terms in the House in the minority; and although he was on Ways and Means, he never accrued any seniority to make it worthwhile (BTW he would have been Chairman in 1995 had he stayed in the House). Likewise, Cheney served ten years in the minority, his tenure as Minority Whip (roughly 1 year) and Minority leader (two plus months); but his position was muted by an overwhelming Democratic majority and by Trent Lott (Minority Leader in 1988).
So, in essence, there has been a massive Congressional brain trust in the Vice Presidency, which has gone largely untapped, and a functional blank slate, in the Presidency, for achieving Executive Branch legislative goals for 32 years (1977 to 2009).
Is presidential success anti-thetical to legislative success? Since 1976, 3 of the Presidents have been re-elected, two have failed. The best explanation for Carter and GHW Bush's failure to get reelected was they had never run for re-election (Bush ran unopposed in 1968). [Note to Romney: your failure to run for reelection may be a bigger political bane than your previous employer, Bain.] Despite that, both played the foreign policy card, GHW Bush better than Carter, to sell the lack of any coherent and successful domestic agenda as a basis for for supporting their reelection.
The three successful Presidents (yes, reelection gives you a leg up in history and how you are viewed success-wise (GW Bush likely would have been viewed as a bigger fraud had he lost in 2004), Reagan, Clinton and GW Bush, had legislative successes to point out. Reagan had budget discipline, tax reform, and deregulation to point out: Clinton had a successful economic turn-around; and GW Bush had the PATRIOT Act, tax cuts and deregulation again. Of course, Reagan had control of the Senate for 6 years. GW Bush had control of the House for 6 years and functional control of the Senate for four plus years from 2001 through 2006. But Clinton controlled the House and Senate for only two years and achieved the most impressive legislative results.
Given the increasing partisanship and deadlock, US Senator may be the best background for a Presidential candidate and if you plan to have your VP carry some of your legislative workload an absolute must for the Vice-Presidency.
In addition to the obvious input, via advice and consent, Senators give on Treaties and Presidential nominations for both the Judiciary and the Executive; Senators know the legislative roadblocks and how to overcome them in the Senate. Gridlock gets broken one of two ways through extremism (ie sharper and more intense partisanship until both sides raise the white flag) and through the more nuanced approach of LBJ and Obama --- vote trading and arm twisting.
When LBJ was President, he needed 67 votes to break a filibuster for the Civil Rights Act. He needed the help of the Senate minority leader, Everett Dirksen of Illinois. LBJ invited Dirksen for a private meeting and breakfast in the Rose Garden. LBJ asked Dirksen for some votes, Dirksen told him basically to pound sand. LBJ said well let's have breakfast. Dirksen and LBJ sat down to Breakfast. Next to Dirksen's plate was the Congressional Record from 25 years prior with then Congressman Dirksen complaining, criticizing and denigrating "Negroes" on the House floor. The "more enlightened 1960s" Senator Dirksen then assured LBJ he would get him whatever votes he needed.
Obama threw in the Cornhusker Kickback in 2010 to get ACA passed and managed an almost unprecedented number of legislative achievements in the 2010 lame-duck sessions.
Of course, the problem with Congressional experience is leads to votes on issues. In the 1970s, a move was put forward to begin recording Congressional votes. In fact, it was pointed out that Kennedy, Johnson, Nixon and Ford were all members of Congress and little to nothing was known of their Congressional careers. So in the late seventies, votes began to be recorded and preserved for history.
And now we have Bob Dole ("Stop lying about my record") and John Kerry ("I vote for it before I voted against it") and Al Gore and Lloyd Bentsen and Dan Qualyle and Jack Kemp and Fritz Mondale and Joe Lieberman and John Edwards and Newt Ginrich and Rick Santorum and Joe Biden and Barack Obama and Hillary Clinton worrying about not their words so much as their deeds.
Less, it seems, is more and the lack of experience is preferential over have a real legislative acumen. When confronted with a controversial or difficult vote, neither pundits nor journalists nor talking heads devote the time and space to explain the context and basis for votes.
When you need to broker a deal, you need to know what to give and what to take and how to declare victory, we've been stuck with President's who obsessively relied on vetoes and veto threats to control the legislative agenda instead. (Kennedy and Johnson never made veto threats, Nixon vetoed few bills as his domestic agenda attracted moderate/conservative Democratic congressional votes. Ford had no tools to work with other than veto power and Carter so mismanaged his relationship with Congress he was overriden on two vetoes when his party was in power. Reagan and GHW Bush regularly threatened vetoes. Clinton threatened fewer vetoes but as a proponent of the line-item veto, he opened the red carpet for expanding signing statements, a practice that really took off when Reagan took office, but ultimately took on an Orwellian evil in the hands of GW Bush.) Things have gotten worse with less Congressional experience not better. Mitt Romney promises more of the same.
Our debates are little more than sound bites. Right or wrong, we, as voters, are entitled to a better view of candidates who might actually make better candidates. Pity, just when it might actually be helpful.