Is Gov. Bob McDonnell's (R-Va.) fall from grace really so surprising?

Alex Burns of Politico expresses incredulity that McDonnell has apparently tossed away his presidential ambitions by accepting gifts like a Rolex watch—and a $120,000 payment that may or may not have been a loan—from one of his top donors.

Most of Burns' sources, Republican and Democrat, share the shock. It's such a petty way to go down.

But politicians risk promising careers for petty reasons all the time. We're not shocked (anymore) when politicians DM naughty pictures to Twitter fans or hire prostitutes while busting prostitution rings. Why should we be shocked if McDonnell risked his career for $120,000 and a Rolex?

Politicians are human. They want sex and money and power like anybody else. They make crass and boneheaded errors in pursuit of them like anybody else.

But at least on the money dimension, we have a way to reduce the likelihood that elected officials will err: Pay them more.

The Governor of Virginia makes $175,000 a year, and that is, in some sense, a lot of money. It's about three times the median household income in the state. It's plenty of money to live a nice lifestyle on.

But it's not nearly enough money to match the lifestyle of the sort of people you become surrounded by when you are a powerful political leader. And while some people have the ability to make peace with that (Pope Francis comes to mind), many don't.

So you get a few phenomena. Politicians rely on the wealth or income of a spouse (Sens. Claire McCaskill and Harry Reid; Secretary of State John Kerry). They decide they can't take it anymore and leave for higher-paying private sector work (Ex-Gov. Sarah Palin and basically every other former senator ever). They run for office only once they're already independently wealthy (Mayor Mike Bloomberg, Former Gov. Jon Corzine).

Or, like McDonnell or Sen. Bob Menendez (D-N.J.), they get sloppy about their financial relationships with their rich friends.

If jobs like Senator and Governor paid about a million dollars a year, these sorts of financial scandals wouldn't totally go away, but they would decline. McDonnell would have had plenty of money to buy his own Rolex.

I encounter two main arguments against paying public officials very highly. One is that we want to attract public-spirited people who aren't in it for the money. The argument goes that public servants should be willing to live on less income than their friends and less than they could make in other work because public service is itself a virtue.

I'm skeptical. I think such public-spiritedness is rare and there are plenty of qualified talents who would be willing to enter public service if it did not entail such a large financial hit compared to other available careers. I also think that public corruption is driven less by a lack of internal virtue than it is by incentives—politicians engage in self-dealing when doing so is appealing and they think they can get away with it.

The other argument is that high pay would disconnect elected officials from the economic situation of their constituents. Politicians should feel financial stress because their constituents feel financial stress.

But I just don't think that system is working. Politicians already find lots of ways to become wealthy other than through salary. Unlike regular people, they always know they have the option of quitting and becoming high-paid lobbyists if pressing financial needs arise. And regardless of what they're paid, top elected officials are going to be elites with a certain amount of disconnection from the public.

Like it or not, top politicians are going to feel entitled to live like they're rich. We can either make them rich by paying them a lot, or we can let them find creative ways to live like they're rich while drawing salaries that are only enough to pay for affluence. The former would be less damaging to the civic fabric than the latter.