Wisconsin Gov. Scott Walker dropped out of college in the spring of his senior year at Marquette University. He never went back for his degree.
It's not clear yet how much this matters politically. Most Americans — nearly 70 percent — don't have a bachelor's degree either, and white voters without a degree particularly tend to lean Republican. On the other hand, this makes him an unusual presidential contender: as the Washington Post points out, the last president who didn't graduate from college was Harry Truman.
Walker's lack of a bachelor's degree might end up mattering. But it shouldn't. Higher education is more economically valuable today than it's ever been, but that doesn't mean a college degree needs to be a prerequisite for the presidency.
The two theories about why college matters
Let's be very clear: college is expensive, but it's still worth it. Wages for high school graduates and for college graduates have been diverging, with high school graduates making less and college graduates making more. In other words, for most people, a college degree is the safest, surest route to a bigger paycheck. Look at this chart from Pew Research:
There are two theories about why a college degree makes such a big difference. Together, they explain why Walker's lack of a degree probably doesn't actually matter.
The first theory is that a college education makes a difference by turning people into better, more productive workers who are worthy of higher wages. This is called the human capital theory. It holds that earning a college degree really does change you, whether by teaching you skills you can use on the job (whether that's something very general, like the ability to think and write clearly, or much more specific, like computer science skills), or by building bigger life skills — such as an ambitious social network or the intrinsic motivation you need to study instead of partying.
The second theory is that employers look for an easy way to separate the wheat from the chaff when hiring. Under this theory, a college degree actually doesn't make you any better at what you're doing. It just serves as an easy signal to employers: this person is a valuable employee, because they are the kind of person who earns a college degree. This is called the "sheepskin effect" — it's the diploma itself, not the work you had to do to earn it, that matters. (Diplomas used to be made of sheepskin, but they mostly aren't anymore.)
Whether a college degree is valuable because of signaling or human capital is a big debate in economics, with real implications for higher education policy. But in Walker's specific case, whichever theory you prefer, the conclusion is the same: a diploma isn't necessary for the presidency.
Why it doesn't matter that Walker didn't earn his degree
Saying that college is mostly a signal doesn't mean a degree is worthless. Signals are valuable. For many people, a college degree is shorthand for someone who values education; for others, it means that you can think critically, argue clearly, and weigh competing evidence. Those are admirable, necessary traits for a president. But they also aren't guaranteed by the mere possession of a college degree. One virtue of the endless presidential campaign cycle is that Walker will have plenty of chances to demonstrate in other ways whether he has those traits or not.
And merely having gone to college yourself doesn't tell other people much of anything about what you believe about higher education's place in society. In 2012, Rick Santorum criticized President Obama for saying more people should go to college, although he has multiple degrees himself.
On the other hand, if a college degree is valuable because of what you learn along the way, Walker probably reaped most of the gains anyway. As the Washington Post made clear, he doesn't lack a college education entirely: he went to Marquette and seems to have attended classes (although he sometimes showed up late to French) while being active in student government. Then he dropped out halfway through his fourth year in college. He was technically a senior, but the Milwaukee Journal Sentinel reported in 2013 that Walker hadn't earned enough credits to get his degree on time — he was 34 credits short of a degree when he dropped out. That still puts about three years of college under his belt.
So the only plausible way to argue that Walker's lack of degree matters to whether he's qualified for the presidency is to say he could have picked up something invaluable in those final 34 credits — something he couldn't have learned in any other way in the 25 years that have passed since then.