President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE's recent posture of blocking former White House officials from appearing on Capitol Hill in response to subpoenas from congressional Democrats is unpopular with the vast majority of the public, according to a new Hill-HarrisX poll.

Nearly three-quarters of registered voters, 74 percent, said they believe that former senior White House officials should be required to testify before Congress when they are subpoenaed, according to the poll. Just 26 percent said they believe that former officials should not have to testify.

Majorities of every demographic group sampled in the May 24-25 poll came down strongly against the idea of allowing ex-White House officials to evade congressional subpoenas. Even Republicans, by a margin of 61 to 31 percent, said that former administration officials should testify before Congress when they are asked to appear.

Independent voters overwhelmingly said that former senior White House employees should submit to congressional subpoenas, with 73 percent in support and 27 percent not. Among Democrats, 87 percent said former administration officials should testify while 13 percent said otherwise.

Voters who called themselves conservative also supported the idea, with 71 percent of respondents who said they leaned conservative in favor of the former officials testifying and 56 percent who called themselves strong conservatives agreeing.

The White House provided numerous documents and witnesses to former special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE and legislative committees examining Russia's involvement in the 2016 presidential election, but the Trump administration has in recent weeks rebuffed many congressional requests, claiming that Democrats are engaging in "presidential harassment."

On Tuesday, House Judiciary Committee Chairman Jerrold Nadler Jerrold (Jerry) Lewis NadlerDemocrats shoot down talk of expanding Supreme Court Schumer: 'Nothing is off the table' if GOP moves forward with Ginsburg replacement Top Democrats call for DOJ watchdog to probe Barr over possible 2020 election influence MORE (D-N.Y.) said that the White House had instructed former communications director Hope Hicks Hope Charlotte HicksSenate intel leaders said Trump associates may have presented misleading testimony during Russia probe: report Cuomo turned down Trump invitation to participate in April press briefing: report Trump shakes up White House communications team MORE and former administration attorney Annie Donaldson to refuse to comply with congressional document requests and subpoenas for their testimony.

"The White House has instructed both Hope Hicks and Annie Donaldson not to turn over records in response to subpoenas issued by our Committee last month," Nadler said in a statement. "The President has no lawful basis for preventing these witnesses from complying with our request."

White House counsel Pat Cipollone replied in a letter obtained by The Hill that it was his belief that the documents sought by Democrats were covered under executive privilege, which some current and former high-level administration officials have cited in refusing certain congressional requests.

While the public appears to support congressional Democrats' attempts to investigate potential wrongdoing by White House officials, a Hill-HarrisX survey released last month found that voters also support an inquiry into whether law enforcement officials acted appropriately when they began the original Russia probe in 2015. That investigation, which Trump has repeatedly called for, included surveillance of people who had been affiliated with the future president's campaign.

—Matthew Sheffield