Just how surprised can he be? Maybe Barack Obama’s more surprised to be the focus of attacks from his fellow Democrats. And maybe the 90%-plus of Democratic voters who view the former president favorably are more surprised. And maybe, just maybe, Joe Biden is the least surprised person about how his competitors for the party’s presidential nomination have had to attack Obama to get to him:

“I was a little surprised at how much incoming there was about Barack, about the president … I don’t think there’s anything he has to apologize for,” Biden said.

He added, “The world has changed since Obama. And here’s the deal. This is about the future. It’s about taking the same kind of integrity and moving beyond it. By the time we ended the president’s term ended, he was able to begin to focus on ways to not just keeping the car from going over the cliff and us going into depression, he was able to begin to focus, and he focused on immigration. And what he did was serious. He changed the dialogue, he changed the whole question, he changed what was going on.”

Er … suuuuure. Biden knew that he would have Obama as a shield going into the election cycle. He’s done everything to wrap himself in the Obama logo except tattoo it under his hair plugs, for Pete’s sake. The calculation was obvious from the start — his competitors would have to dance around attacks on Obama or face criticism for attacking the very, very popular former president.

As for being “about the future,” that’s another knowingly disingenuous argument. Biden’s running for Obama’s third term; even this statement promises to pick up where Obama left off. If the Democrats wanted to run a campaign “about the future,” they wouldn’t choose a 76-year-old nominee who’s been in Washington for nearly fifty years. About the future, indeed.

Democrats had better start worrying about the near-future, however, if they continue to attack Obama as insufficiently progressive. As I write in my column at The Week, they’re pushing to the extremes, and don’t think voters won’t notice:

Why would Democrats attack their most popular figure in their own primary? Booker later tried justifying it by claiming that the party needs “an honest conversation” about Obama’s legacy. While Trump is “perverting our very values and ideals,” Booker claimed, Democrats also need to talk about how “our plans would be different from the previous president, different from the current president.”

That is a very risky strategy. Obama was hardly a centrist while in office, but succeeded in large part because of his personal connection to voters and an ability to keep the center engaged. Democrats had already lurched to the left in this cycle, but attacking Obama on issues like health care and immigration is practically a declaration of extremism to most voters. That will cost them at the ballot box, perhaps most particularly in those suburbs that gave Democrats a House majority in the midterms.

Furthermore, it sets up an implicit equivalency between Trump and Obama that won’t play well at all for Democrats outside of their activist base. Booker hinted at it in his defense, suggesting that Trump and Obama aren’t that far apart on policy, which is actually true on issues like deportations and keeping “babies in cages and separat[ing] children from their parents,” as Harris fumed on Wednesday. The Associated Press reminded its readers during the debate that the Obama administration did both too. Such attacks not only make Democrats look more radical, they make Trump look more mainstream at the same time.

That alone may have made Trump the Democratic debate’s biggest winner by the end of its second round. If nothing else, Barack Obama was certainly its biggest loser, without a single Republican voice on the stage. Democrats should ask themselves which president they truly want to run against.

Don’t worry too much about that advice, Republicans. As long as Biden remains the frontrunner, Obama will inevitably be attacked, and Democrats will keep looking more and more radical. And we’ll just keep passing more and more popcorn.