Former Vice President Joe Biden denounced the “demeaning” state of politics in a speech in Philadelphia on Sunday.

Biden spoke before presenting the National Constitution Center’s annual Liberty Medal to former President George W. Bush and former first lady Laura Bush.

“President Bush was my opposition … he was never my enemy,” Biden said in his remarks. “Think how demeaning our politics has become in terms of how we talk about one another.”

{mosads}The award is presented to individuals for their commitments to veterans. Other past recipients have included Hillary Clinton, Malala Yousafzai and Nelson Mandela.

Biden, the chairman of the National Constitution Center’s board of trustees, also presented the medal to the late Sen. John McCain (R-Ariz.) last year.

Biden underscored the importance of democratic values and patriotism in his remarks, praising Bush for his support for service members and their families.

“We share a belief that those values which undergird our democracy are precious, and they exist way above party, and they have to be defended,” Biden said. “That’s the duty of patriots.”

The ceremony was disrupted by protests from veterans groups, according to local reports. Veterans Against the War, a group of post-9/11 service members and veterans, protested outside the center, while others blocked the entrance. At least one protester interrupted Biden’s remarks, and was escorted out by security.