Former Vice President Joe BidenJoe BidenBiden administration still seizing land near border despite plans to stop building wall: report Olympics, climate on the agenda for Biden meeting with Japanese PM Boehner on Afghanistan: 'It's time to pull out the troops' MORE 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.”

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The award is presented to individuals for their commitments to veterans. Other past recipients have included Hillary ClintonHillary Diane Rodham ClintonChelsea Clinton: Pics of Trump getting vaccinated would help him 'claim credit' Why does Bernie Sanders want to quash Elon Musk's dreams? Republican legislators target private sector election grants MORE, 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.