The ranking Republican on the House committee investigating the Nov. 24 White House security breach by Tareq and Michaele Salahi is not backing down from demands that the White House social secretary Desiree Rogers testify before Congress.

On "Good Morning America" Friday, Rep. Peter King, R-N.Y., said the White House refusal to let Rogers answer questions on the basis of separation of powers amounts to "smacking Congress in the face."

"I think she should come up and explain what happened," King told ABC News' Bill Weir. "All I'm saying is they owe it to the Congress, they owe it to the American people to explain why for the first time in 20 years she decided to have no one from her office working with the Secret Service."

In testimony Thursday, Secret Service director Mark Sullivan said agents did not receive assistance from White House staff checking-in guests at the initial checkpoints on Nov. 24 – a break from previous administrations. King wants to Rogers to explain why that decision was made.

The White House insists it doesn't need to explain itself.

"I think, you know, that, based on separation of powers, staff here don't go to testify in front of Congress. She won't. ... She will not be testifying in front of Congress," White House press secretary Robert Gibbs told reporters Wednesday.

Rep. King called Gibbs' "offhand answer" unacceptable and said Rogers' testimony has "nothing to do with any private dealings" with the president.

"I think [Gibbs] has sort of been a wise guy on this, flippant remarks at the news conferences," said King. "He said I had the audacity to bring this issue up. As I said, the only audacity I have is the audacity of hope that this White House will be honest. And so far they're not being honest on this issue."

The chairman of House Homeland Security committee, Rep. Bennie Thompson, D-Miss., said he intends to subpoena the Salahis to testify but blocked King's request to subpoena Rogers as well during Thursday's hearing.

"I believe there is a clear distinction here between Ms. Rogers and the Salahis… her role does not encompass security," Thompson said. "It would not be prudent to expend resources in protracted fight with the White House when the testimony sought" is not integral to security of the president.

Rep. King, the committee's top Republican, emphatically disagreed.

"I think it's wrong. I think it's stonewalling. It was a bipartisan request" to have her appear before the committee, Rep. King said.

Salahis Likely To Get Unwanted Invitation: A Subpoena

The aspiring reality-TV stars also did not appear before the House Homeland Security Committee yesterday, their seats empty as chairman Rep. Bennie Thompson, D-Miss., issued the threat of subpoena.

"You know, they've been just about on every network TV available," he said. "We are now asking them to come before the committee."

Earlier, U.S. Secret Service Director Sullivan told the panel the Salahis are targets of a criminal investigation after gaining access to White House grounds when they apparently did not have an invitation.

Sullivan bluntly admitted his agency was primarily to blame for the incident, accepting full responsibility for what he called an "unforgiveable and indefensible" mistake.

The Secret Service director acknowledged protocols were not followed at one state dinner checkpoint, where at least one agent actually checked a guest list for the Salahis' names and, not finding them there, still allowed the couple to proceed to the next checkpoint inside the White House complex.

"Human error occurred in the execution of our duties," Sullivan said. "A mistake was made. In our line of work, we cannot afford even one mistake."

Three agents have been placed on paid administrative leave while the investigation is pending, Sullivan told the committee.

"We are all fortunate that this diplomatic celebration did not become a night of horror," said chairman Thompson.

Committee Grilled Sullivan For Answers

"How is the world could this couple get past the Secret Service and get right up to the president of the United States?" asked a perplexed Rep. Michael McCaul, R-T.X.

"I have asked myself that question a thousand times this week," replied Sullivan.

Sullivan said the Secret Service and White House staff agreed during a planning meeting before the state dinner that agents would control the guest list at various entry points.

But when asked if a member of the White House staff stationed at the entry checkpoint could have prevented the Salahis from getting in, Sullivan said "it would have helped."

White House social secretary Desiree Rogers attended the Nov. 24 state dinner as a guest and told reporters which designer's dress she was wearing.

"Why would you all agree that no person from the White House would be standing there – first of all to greet guests, but at the same time if there were problems, to immediately be able to take care of them?" Rep. Loretta Sanchez, D-Calif., asked Sullivan.

"I would acknowledge that is very rare," Sullivan said. "I believe the memo put out by the White House yesterday -- they recognize that as well.

That memo – by Deputy White House Chief of Staff Jim Messina – instructs Rogers' office to abide by precedent and have a White House staffer present at checkpoints during future official events.

"After reviewing our actions, it is clear that the White House did not do everything we could have done to assist the United States Secret Service in ensuring that only invited guests enter the complex," Messina wrote.

Rogers was invited to testify before the House panel Thursday but did not come.