House Democrats told no-show witness Harriet Miers on Friday that she could soon be held in contempt as they issued the Republican National Committee a new subpoena for White House e-mails.

The deadline for replies from both: Tuesday.

Miers, President Bush's former legal counsel who a day earlier defied a subpoena to appear before the House Judiciary Committee, could be held in criminal contempt of Congress if she fails to notify the panel by Tuesday that she has changed her mind and will appear, according to a letter sent to her attorney by Committee Chairman John Conyers, D-Mich.

Though instructed by Bush to skip the hearing to which she was subpoenaed, Miers — not Bush — owns that decision and could be punished for it, Conyers wrote.

"Ms. Miers could not legally be compelled by the White House to disregard the subpoena, but instead made her own decision to disregard it," Conyers wrote to Miers' lawyer, George Manning of Atlanta.

Conyers repeated that Miers' failure to "promptly mitigate her noncompliance could subject her to contempt proceedings."

The toughly worded letter was an incremental step toward launching any such proceedings, which would first be considered by the committee and later by the full House. If a majority of the House approves a contempt order, Speaker Nancy Pelosi, D-Calif., would refer the matter to the U.S. attorney for the District of Columbia, Jeff Taylor, a Bush appointee.

Two knowledgeable Democratic aides said committee members and House leaders were preparing for contempt proceedings in case negotiations advance no further.

The dispute showed no signs of being resolved. Instead, the standoff has escalated into a broader fight over the limits of executive power that touches on other congressional investigations — from the FBI's abuse of civil liberties under the USA Patriot act to Bush's secretive wiretapping program.

Conyers added more fuel to the fight Friday when he issued a subpoena to the RNC for e-mails on the firings sent by White House officials on RNC-sponsored accounts. White House legal adviser Emmet T. Flood instructed RNC lawyer Robert Kelner on July 9 to withhold virtually all of those e-mails "without prior authorization to the White House."

Congressional Democrats probing whether the White House ordered the firings to help Republican candidates want to interview current and former administration officials on their roles in the dismissals. Bush and Attorney General Alberto Gonzales have denied any wrongdoing, pointing out that federal prosecutors are political appointees who can be fired by the president for almost any reason.