At the 2016 White House Correspondents' Association Dinner, Barack Obama performed the last of his presidential stand-up routines before the assembled crowd of journalists and political heavyweights. He opened with a joke about Hillary Clinton and one of the political controversies that she just couldn't shake in her campaign for the presidency: paid speeches she gave to Wall Street bankers. "Here we are, my eighth and final appearance at this unique event," Obama said. "And I am excited. If this material works well, I'm going to use it at Goldman Sachs next year. Earn me some serious Tubmans. That's right."

It was a decent joke and everyone laughed. And then Obama added an additional layer of irony to the gag by waiting about three months after leaving office to accept some serious Tubmans for a Wall Street speaking engagement.

The details of Obama's Wall Street speaking fee have been exhaustively reported at this point. He's going to haul in a meaty $400,000 to give a speech at a health-care conference hosted by Cantor Fitzgerald, a capital investment firm. This is an extremely normal thing for an ex-president or other high-ranking government officials to do — they wrap up their time in public service and trip over themselves to cash in on the speaking circuit. This is how Newt Gingrich can afford penguin safaris in Antarctica. So it's reasonable, then, for Obama to line his pockets in the same way, yes?

Well, not really. No. For Obama, collecting mammoth Wall Street speaking fees is a repudiation of his own political brand that could cause problems for his party in the era of President Trump.

Before we get to the politics, let's take a quick look at the practical considerations at play. As a former president, Barack Obama will never, ever lack for funds. He's already reportedly signed a book deal for something like $60 million. If that money ever runs out, he could walk into any big publishing house and demand another $60 million for another book. For all the remaining years of his life, Barack Obama can and will make an obscene amount of money simply by being Barack Obama. So I'm sure the extra $400,000 he'll get for this one speech will be appreciated and well spent, but there's no actual need for him to accept a sum like this from a financial investment firm.

And that brings us to the politics. Obama rose to the presidency as the country sank into the trough of the Great Recession. He campaigned against the financial sector malfeasance that nearly collapsed the economy, promising to "bring a new era of responsibility and accountability to Wall Street." Obama's record as president when it came to Wall Street accountability was mixed — new regulations and consumer protection agencies provide some check on financial sector criminality, but the people responsible for corroding the economy with toxic mortgage debt got off clean. Taking a huge speaking fee from a Wall Street firm tells us that Obama's aspirational theory of "change" is tempered by the baser desire to cash in on one's public service wherever possible.

That is not the message a prominent Democrat should be sending as the party grapples with the Trump presidency.

The 2016 election should have taught Democrats that Wall Street is politically toxic and that Wall Street speaking fees are a dangerous and potent issue. Hillary Clinton never had a good answer for why her Goldman Sachs speeches did not compromise her politically, and it stung her in both the Democratic primary and the general election. Donald Trump used the speeches to argue that she was irredeemably corrupt and nurture the idea that she was just as ethically compromised as he was.

After taking office, Trump promptly handed that sword right back to the Democrats by staffing his administration with a small army of Goldman Sachs executives and promptly deregulating the financial sector. This gives Democrats an opening to reclaim some populist cred and attack Trump for being what he is: a corrupt and self-interested crony of the nation's financial elite. That task becomes more difficult when Obama — who is still the nation's most prominent Democrat and the de facto leader of the party — is collecting six-figure speaking fees from investment firms.

As a matter of political and civic health, Obama shouldn't go through with the speech. Or if he does, he should donate his fee to charity (like, say, to a group that helps distressed homeowners stave off foreclosure).

Obama is, of course, free to make money however he sees fit in his post-presidency. But there are better, less politically compromising ways to rake in those Tubmans than selling out to Wall Street.