Of the many strange moments in the Bowe Bergdahl saga, the most worrisome was Defense Secretary Chuck Hagel’s statement about the prisoner exchange.

“The president feels very strongly about this. I feel very strongly about it,” Hagel told the BBC’s Katty Kay last week while traveling in Romania. “This was the right decision for the right reasons.”

They felt they were right even about rushing the swap with the Taliban before informing Congress. “It was our judgment, and it was unanimous, by the way,” Hagel said. “It was the secretary of defense, secretary of state, chairman of the joint chiefs of staff, director of national intelligence, attorney general. We all came to the same conclusion.”

And this is precisely the problem. President Obama felt “very strongly” that he had made the right decision – and nobody who worked for him was about to tell him otherwise. “There was not a dissent on moving forward with this plan,” Ben Rhodes, a deputy national security adviser, told Time magazine.

I don’t doubt these accounts about Obama’s agreeable advisers. Such affirmations of Obama’s instincts are what has worried me about the way Obama has structured his administration in his second term: By surrounding himself with longtime loyalists in the White House and on his national-security team, he has left himself with advisers lacking either the stature or the confidence to tell him when he’s wrong.

Exactly a year before Hagel made his remarks, I wrote about the “incestuous arrangement” that Obama was creating in his inner circle, replacing his first-term “team of rivals” by promoting friends and loyalists to top posts: Denis McDonough, John Brennan, Susan Rice, Samantha Power, Jack Lew and many more. Hagel, Secretary of State John Kerry and Vice President Biden were all Obama’s pals from the Senate Foreign Relations Committee. The danger with such an arrangement is you create a bubble around yourself, and your advisers become susceptible to groupthink.

In the Bergdahl case, the problem wasn’t the exchange itself. There are compelling moral and historical justifications for swapping prisoners at the end of a war, and the Republican efforts to turn the negotiations with the Taliban into another “scandal” are far-fetched. As The Washington Post’s David Fahrenthold and Jaime Fuller have documented, many of Obama’s critics have opportunistically switched positions on Bergdahl.

The real damage was self-inflicted: choosing to highlight the exchange with a Rose Garden ceremony featuring Bergdahl’s eccentric father, and then allowing Rice, the national security adviser, to go on television and say Bergdahl served with “honor and distinction” even though administration officials had to know this was in dispute.

Even if Obama doubted the constitutionality of the law requiring him to give Congress 30 days’ notice before removing prisoners from Guantanamo Bay, would it really have been a huge security risk to place phone calls to Sen. Dianne Feinstein, D-Calif., and Rep. Mike Rogers, R-Mich., the intelligence committee chairmen, before he finalized the deal?

I’m told that Obama’s advisers didn’t check with Congress in part because they knew lawmakers would object. But now Obama is hearing objections from the public instead. A USA Today/Pew Research poll out Tuesday shows that a majority of Americans believe the United States had a responsibility to bring Bergdahl home. But by 2 to 1, Americans think the president should inform Congress before making prisoner swaps, which helps explain why a plurality, 43 percent to 34 percent, say Obama was wrong to make the Bergdahl deal.

More than a decade ago, a different administration’s groupthink got us into a war in Iraq, which distracted the military from the more important war in Afghanistan and unnecessarily prolonged that conflict. Now, as Obama finally withdraws the last troops from Afghanistan, he’ll be a more effective president if he can also remove himself from the groupthink produced by his adoring acolytes.

Dana Milbank is a columnist for The Washington Post. He can be contacted at:

danamilbank@washpost.com