Former White House aide refuses to testify in impeachment probe

Schiff said it was yet another example of the White House engaging in obstruction of a Congressional investigation - which could easily form the basis for an article of impeachment.

"If this witness had something helpful to say for the White House, they would want him to testify," Schiff told reporters.

"They plainly don't," Schiff added.

Asked by reporters if the House would go to court to compel Kupperman to testify, Schiff indicated that Democrats might not, wanting to avoid a time consuming legal fight.

"We will not allow the White House to delay our investigation," Schiff told reporters after Kupperman refused to follow a subpoena for his testimony.

Meanwhile, a legal battle continued between the House Judiciary Committee and the Justice Department, as the Trump Administration asked for a Friday ruling to be put on hold - that decision ordered the feds to turn over grand jury evidence accumulated in the Mueller probe by Wednesday.

Last Friday, a federal judge ordered the Mueller materials be released to the House Judiciary Committee, to further the impeachment investigation by Democrats.

"The Department of Justice ("DOJ”) claims that existing law bars disclosure to the Congress of grand jury information," Judge Beryl Howell wrote.

"DOJ is wrong," Howell wrote, saying there was no reason Congress should not benefit from the details of the Mueller investigation, repeatedly citing the rulings of federal judge John Sirica during Watergate.

“It should not be forgotten,” he explained, “that we deal in a matter of the most critical moment to the Nation, an impeachment investigation involving the President of the United States," Howell wrote, quoting Sirica.

Judge Howell has given House Judiciary Democrats until 12 noon on Tuesday to respond to the motion by the Justice Department to put her Wednesday deadline on hold.