The House Judiciary Committee voted Wednesday to hold attorney general William Barr in contempt of Congress.

The  move escalates the Democrats’ extraordinary legal battle with the Trump administration over access to special counsel Robert Mueller’s Trump-Russia report.

The vote capped a day of ever-deepening dispute between congressional Democrats and President Donald Trump.

For the first time he invoked the principle of executive privilege, claiming the right to block lawmakers from the full report on Mr Mueller’s probe of Russian interference to help Mr Trump in the 2016 election.

House Judiciary Committee Chair Jerrold Nadler
House Judiciary Committee chairman Jerrold Nadler (J Scott Applewhite/AP)

Committee chairman Jerrold Nadler declared the action by Mr Trump’s Justice Department a clear new sign of the president’s “blanket defiance” of Congress’ constitutional rights.

“Every day we learn of new efforts by this administration to stonewall Congress,” Mr Nadler said. “This is unprecedented.”

But White House press secretary Sarah Sanders said it was rather a response to the “blatant abuse of power” by Mr Nadler, a Democrat.

“Neither the White House nor attorney general Barr will comply with chairman Nadler’s unlawful and reckless demands,” she said.

Though the White House initially hesitated on invoking privilege, Mr Trump told his staff and political advisers in recent weeks to refuse to co-operate with Democrats, believing the party’s goal was simply to damage him politically going into his re-election campaign.

The coming legal battle could stretch to 2020, and the White House is aiming to tie up congressional probes until election day.

Executive privilege is the president’s power to keep information from the courts, Congress and the public to protect the confidentiality of the Oval Office decision-making process.

The president’s decision was weeks in the making, the next inevitable escalation between the White House and Congress over a number of probes.

The White House has rejected all efforts to probe Mr Trump’s business dealings or tax returns as well as the West Wing’s security clearance procedure.

The committee voted along party lines, 24-16, to hold Mr Barr in contempt but only after some five hours of heated and, at times, emotional testimony.

Democrats, who have the majority in the House, made their case that Congress was at a historic juncture as it confronts what they consider Mr Trump’s stonewalling of lawmakers’ ability to conduct oversight of the administration.

Republicans portrayed the majority as angry and lashing out at Mr Barr after the special counsel did not find that Mr Trump colluded with Russia to swing the 2016 election.

House Speaker Nancy Pelosi said the next step after the committee vote will be consideration by the full House.

If approved by the House, where the Democrats hold a solid majority, the contempt resolution would almost certainly move to an unusual, and potentially protracted, multi-pronged court battle with the Trump administration.