Sen. Angus King, I-Maine, steps into an elevator as he departs the Senate following defense arguments by the Republicans in the impeachment trial of President Donald Trump on charges of abuse of power and obstruction of Congress, at the Capitol in Washington on Saturday. Credit: J. Scott Applewhite | AP

Acquitting President Donald Trump of obstruction during his impeachment trial could reshape the power structure between the president and Congress forever, creating graver implications than the abuse-of-power claims, Sen. Angus King said.

Allowing a president to thumb his nose by refusing to cooperate with a congressional investigation would set a dangerous precedent, giving the president power to operate without congressional oversight, King said.

“It would be the largest transfer of power from the Congress to the executive in the history of the country,” he told The Associated Press.

King, an independent from Maine, made his comments after Trump’s lawyers began his impeachment defense Saturday in the Senate. Trump is accused of abusing his power when he asked Ukraine to investigate political rival Joe Biden in a July 2019 call, and then obstructing Congress as it tried to investigate.

King said he hasn’t fully made up his mind on either of the two articles of impeachment, but he said he’ll be arguing to fellow senators that allowing the president to block a congressional investigation amounts to an abdication of Congress’ authority.

“I’m going to strongly make this point to my colleagues,” he said. “It’s a question of the checks and balances and the basic structure of our Constitution.”

He said the Trump administration erred in providing not a single witness or document to the House impeachment probe, allowing the president to try to avoid the checks and balances that the framers of the Constitution intended.

“This has nothing to do with Donald Trump. This has to do with the next president, the next president, and the next president. Whether it’s Benghazi or Fast and Furious, it’s fundamental to the Congress’ ability to hold the executive to account,” he said, referring to two previous congressional investigations.