Trump puts it in writing he won't co-operate in impeachment probe

The White House declared Tuesday it will not co-operate with what it termed an "illegitimate" impeachment probe by House Democrats, setting up a constitutional clash between U.S. President Donald Trump and Congress.

Trump lawyerssent a letter to House leaders bluntly stating their refusal to participate in the quickly moving impeachment investigation. The letter threatens to cease co-operation with Capitol Hill on key oversight matters, accusing lawmakers of formulating their probe "in a manner that violates fundamental fairness and constitutionally mandated due process."

"Given that your inquiry lacks any legitimate constitutional foundation, any pretence of fairness, or even the most elementary due process protections, the Executive Branch cannot be expected to participate in it," White House Counsel Pat Cipollone wrote.

The White House is objecting that the House did not formally vote to begin the impeachment inquiry into Trump and is also attacking the conduct of House intelligence committee chairAdam Schiff.

House Speaker Nancy Pelosi has insisted the House is well within its rules to conduct oversight of the executive branch under the U.S. Constitution regardless of a vote.

The letter comes the same day that Trump intensified his fight with Congress, with the State Departmentblocking Gordon Sondland, the U.S. ambassador to the European Union, fromtestifying behind closed doors before three congressional committeesabout the president's dealings with Ukraine.

House Democrats followed up by issuinga subpoenato have Sondland testify, on Oct. 16, after he was directed not to appear before the committeesas planned on Tuesday morning.

Sondland'slawyer, Robert Luskin, said his client was "profoundly disappointed" that he wouldn't be able to testify. And Schiff said Sondland's no-show was "yet additional strong evidence" of obstruction of Congress by Trump and Secretary of State Mike Pompeo that will only strengthen a possible impeachment case.

A whistleblower's complaint and text messages released by another envoy portray Sondland as a potentially important witness in allegations that the Republican president sought to dig up dirt on a Democratic rival in Ukraine and other countries in the name of foreign policy.

Intelligence committee chair Adam Schiff said the cancellation took him by surprise, as the committee members had flown back to Washington for what was a special session.

Characterizing the administration's decision as "further acts of obstruction of a co-equal government," Schiff said the committee had also been denied access to pertinent text messages involving Sondland.

Listen: Historian on Trump impeachment prospects

Pelosi said thwarting the witness testimony on Tuesday was an "abuse of power" in itself by the president.

A senior administration official told reporters that no additional witnesses under its purview will be permitted to appear in front of Congress or comply with document requests, saying the policy under the current circumstances is that the administration will have "a full halt" because "this is not a valid procedure" for an impeachment inquiry. The official spoke on the condition of anonymity to discuss the administration's position.

The White House is claiming that Trump's constitutional rights to cross-examine witnesses and review all evidence in impeachment proceedings extend even to House investigations, not just a potential Senate trial. It also is calling on Democrats to grant Republicans in the House subpoena power to seek evidence in the president's defence.

Sondland is best known in the Pacific Northwest as the founder of the Provenance Hotels chain.

He supported Jeb Bush in the 2016 Republican primaries, but after Trump emerged as the Republican nominee, four limited liability corporations controlled by Sondland gave the Trump inaugural committee at least $1 million US, according to Federal Election Commission records and business filings.

He was nominated by Trump for his current role in May 2018 and confirmed by the Senate just over a month later.