America's last four presidents have each graduated from Harvard or Yale. And indeed, most American presidents have been well educated. Of the 43 men who have been president (Yes, Obama is 44, but Grover Cleveland was number 22 and 24), just nine — Abraham Lincoln among them — didn't earn a degree. Of those, seven — again, including Lincoln — never went to college at all

Most of these exceptions date back to the Civil War era or earlier. In the last 125 years, Americans have elected just one president who didn't finish college: Harry Truman.

Today, Truman is ranked by historians as one of America's 10 best presidents. He led America through the final months of World War II, stood up to the communists in Berlin and Korea, and oversaw the creation of NATO.

Why is this relevant today? Because Wisconsin Gov. Scott Walker — a serious contender for the GOP nomination next year — never graduated from college.

It's not like Walker has never been on campus. He attended Marquette University from fall 1986 to spring 1990, triple majoring, he said at the time, in political science, philosophy, and economics. In February 1990, he took a job at the American Red Cross and dropped out of school three months later. "I'm someone who went to college, had the opportunity in my senior year to go and take a job full-time," he says, "and I took it, thinking someday, maybe, I'd go back." Instead he got married and became a father. He was a senior "in good standing" when he left, Marquette says, debunking Democratic claims that Walker was kicked out of school.

Walker's lack of a college degree shouldn't matter. His real-word experience is vastly more important and impressive.

While no job can truly prepare you for the presidency, the executive experience accumulated from running a state comes closest. Four of the last six presidents — Jimmy Carter (Georgia), Ronald Reagan (California), Bill Clinton (Arkansas), and George W. Bush (Texas) — were governors. In this respect, Walker, who has passed muster with Wisconsin voters three times (including beating back a recall attempt in 2012), is more than qualified to serve as commander-in-chief.

But qualifications and electoral success in his home state aside, would Americans accept a president who didn't graduate from college? Should they? 

A college education has traditionally been seen as a path to a greater future, and for many Americans, that's exactly what it has proven to be. It can broaden one's horizons. It can open doors. But it can also leave you up to your neck in debt, with no job and no upward mobility. 

For many Americans, college today is seen as a financial burden, even a rip-off that might not be worth it. The average member of the class of 2014, for example, graduated $33,000 in the hole. Most grads still say it's worth it, given that they'll likely earn more than non-grads over the long run. Even so, that's still a ton of debt to shoulder. 

So for someone to leave school to join the workforce — as Walker did — will likely be seen as understandable by many voters. A good job is a good job. Americans understand that, particularly in today's trying economic times.

Whether you like Walker politically or not, you must concede that the guy has pulled himself up the ladder and made something of himself. Unlike, say, the Bushes or Kennedys — political families that sprang from wealth and privilege — Walker is the son of a bookkeeper and minister. That's the kind of up-by-the-bootstraps story that resonates with voters. If anything, blue-collar voters might like Walker not in spite of the fact that he didn't finish college, but because of it.

Indeed, Walker's persona may really resonate with the growing number of Americans who distrust elites and elite institutions. Conservatives like to rail against ivory-tower academics who don't live in the real world; Walker's lack of a degree is no handicap in that respect — it's a credential.

Lyndon Johnson (Southwest Texas State Teachers' College) and Ronald Reagan (Eureka College) didn't exactly receive world-beating educations. I don't think it had even the slightest impact on their presidencies. 

And if the people who know Scott Walker better than the rest of us — the voters of liberal Wisconsin — can elect a conservative dropout not once but twice, well, perhaps there's your answer right there.