During Sunday night’s Democratic presidential debate in South Carolina, Bernie Sanders made one basic argument for why America needs to put him in the Oval Office. Not quite this explicitly, but almost, Sanders asserts:

The game is rigged by the Big Money. Millionaires and billionaires and Wall Street banks and Fortune 500 corporations and Chatsworth Osborne Jr. (that’s a Dobie Gillis reference) own American politics in ways that guarantee they cannot lose and almost always win, which means ordinary Americans almost always lose. The Big Money guys are too big to fail and too big to jail, so even if they collude in a way that crashes the U.S. economy, they don’t go broke and they don’t go to prison.

Wall Street controls not only the Republican Party (the semi-official party of fat cats) but has also bought insurance by corrupting important elements of the Democratic Party, including Hillary Clinton, at least according to Sanders (and I don’t mean to imply by that phrasing that I find his argument absurd).

In case you think I’m exaggerating the fundamental nature of this argument, here’s one of several quotes from the debate, starting with a question from NBC moderator Lester Holt:

HOLT: Senator Sanders, you released a tough new ad last week in which, without mentioning Secretary Clinton by name, you talk about two Democratic visions for regulating Wall Street. “One says it’s OK to take millions from big banks and tell them what to do. My plan, break up the big banks, close the tax loopholes and make them pay their fair share.” What do you see as the difference between what you would do about the banks and what Secretary Clinton would do?

SANDERS: Well, the first difference is I don’t take money from big banks. I don’t get personal speaking fees from Goldman Sachs.

What I would do is understand that when you have three out of the four largest banks today, bigger than they were when we bailed them out because they were too big to fail, when you have the six largest financial institutions having assets of 60 percent of the GDP of America, it is very clear to me what you have to do.

You’ve got to bring back the 21st century Glass-Steagall legislation and you’ve got to break up these huge financial institutions. They have too much economic power and they have too much financial power over our entire economy. If Teddy Roosevelt were alive today, the old Republican trust-buster, what he would say is these guys are too powerful. Break them up. I believe that’s what the American people want to see. That’s my view.

Buying elections

Over the course of the evening, Sanders made several references to the SuperPAC and Citizens United-bedeviled campaign finance structure, like this one: “We have a corrupt campaign finance system where millionaires and billionaires are spending extraordinary amounts of money to buy elections.”

And when he says that his campaign “is about a political revolution to not only elect the president, but to transform this country,” he means quite clearly that the kind of change he recommends, the kind that would help the lower and working and middle classes, cannot be enacted by political leaders who are indebted to Wall Street.

Lest there be any doubt, the person to whom he was alluding, who does get money from big banks and speaking fees from Goldman Sachs, is Hillary Clinton, who in 2013 — the year she left her position as secretary of state — was paid $675,000 by Goldman Sachs for three speeches (part of a total of $2.9 million she received as personal income for giving 12 speeches to Wall Street banks).

And, according to the same article linked to above, Clinton’s husband, former President Bill Clinton, earned $17 million in talks to banks, insurance companies, hedge funds, real-estate businesses and other financial firms. Altogether, the couple is estimated to have made more than $139 million from paid speeches in an eight-year period.

Maybe you believe Wall Street pays all that money just to hear good speeches. Maybe you don’t. Sanders at least wants you to wonder about it.

The race between Sanders and Clinton has been civil. They generally do not make personal attacks on each other and frequently express respect and friendship. Compared to the all-out war for the Republican nomination, the race on the Dem side — including last night’s debate — is a model of substance, civility and factual accuracy.

And yet, it is not possible avoid the conclusion that Sanders believes Hillary Clinton is too corrupted or compromised by the Wall Street money she and her husband have been paid to be the person who would govern in the interest of what the Occupy Wall Street movement used to call “the 99 percent,” or whom Sanders likes to address as “brothers and sisters.”

There were, of course, a lot more subjects discussed last night, most of them worthy of discussion and many of them worth considering for Democrats trying to decide whom to support for the nomination.

There is the question of which Democrat would be most likely to win in November and which candidate would have the skills to smuggle some of their policy preferences past the gridlock in Washington.

But I’m determined to keep this piece fairly short and, to me, the most interesting, slightly-below-the-surface argument made by candidates is Sanders’ claim that Clinton has been bought and he is unbought.