A senior aide to U.S. Sen. Michael Bennet (D-Colo.) was shouted down by a group of environmental protestors for suggesting nominees for Cabinet positions should be treated fairly during the Senate confirmation process.

The protest, held Jan. 9 in Denver, was organized by 350.org, the nation’s leading “keep it in the ground” group. About 40 protestors gathered outside Bennet’s office demanding that he oppose the confirmation of U.S. Rep. Ryan Zinke for Interior Secretary, Oklahoma Attorney General Scott Pruitt for administrator of the U.S. Environmental Protection Agency, former Texas governor Rick Perry for Energy Secretary, and Rex Tillerson for Secretary of State.

Bennet’s state director, Rosemary Rodriguez, spoke to the protestors in front of the senator’s office. The Democratic staffer was cheered and applauded – until she suggested that Trump’s nominees receive a fair hearing.

“We are going to abide by the process,” Rodriguez said.  “We’re going to respect the president – the incoming president – and his appointees.”

“Why?! Why?!” the protestors shouted in response. “Respect our process!” one of the protestors demanded.

The Colorado chapter of 350.org recorded the exchange and then uploaded the video to YouTube.

This isn’t the first time Bennet has angered “keep it in the ground” activists. Ahead of his successful 2016 reelection campaign, he voted in favor of legislation authorizing the Keystone XL pipeline project, breaking with the Obama White House and anti-fossil fuel groups.

In response, activists with 350.org and other anti-fossil fuel groups protested a Bennet fundraiser and threatened to “find a candidate who values their community.” But no other Democrat challenged Bennet and he won his party’s primary unopposed.