The Pentagon's No. 2 civilian, questioned by a congressional panel on the difficult U.S. campaign in Iraq, asserted anew Tuesday that Saddam Hussein (search) was a brutal dictator and Iraq is better off without him.

Sen. Edward M. Kennedy told Deputy Defense Secretary Paul Wolfowitz (search) his testimony before the Armed Services Committee was "somewhat disingenuous."

Kennedy, D-Mass., faulted Wolfowitz for offering testimony that focused on human rights under Saddam's rule rather than the administration's main rationale for going to war last years — the allegation that Saddam had an arsenal of weapons of mass destruction.

The hearing was among five question-and-answer face-offs Congress scheduled for administration officials this week amid increased anxiety on Capitol Hill about the course of the war. Wolfowitz gave a half-hour statement focusing mostly on administration claims about the abuses of Iraqis under Saddam and progress occupation forces have made since his ouster.

As Wolfowitz testified on Iraqi operations before the Armed Services panel, Senate Foreign Relations Committee Chairman Dick Lugar criticized the administration, at another hearing, for the Pentagon's refusal to testify later this week on the planned June 30 transition to Iraqi sovereignty.

Saying success in Iraq depends on the administration's credibility, Lugar noted that over the past year and a half the administration has "failed to communicate" its plans to Congress and the American people. And it may be missing another chance by not showing up Thursday, he said Tuesday, opening the first of his committee's three hearings.

Sen. John Warner, R-Va. and chairman of the Armed Services panel, opened his hearing noting the rise in violence in Iraq this month and saying insurgents "seek to delay their inevitable defeat" by occupation forces.

"The importance of this hearing cannot be overstated," said Warner. "We are at a critical juncture ... in both Iraq and Afghanistan."

Throughout the week's hearings, officials are likely to face questions on what is being done to calm the increased violence in Iraq, whether troop levels are high enough and exactly how the administration intends to work with the United Nations (search). U.S. occupation authorities, who long shunned a substantive U.N. role in Iraq, are now counting on it to help devise a plan for forming a new Iraqi government to accept sovereignty on the turnover date.

Democrats are expected to ask about mistakes of the past that they say have brought the administration to this point. And Sen. Carl Levin, top Democrat on the Armed Services panel, said Tuesday it was necessary to do that in order to more forward.

"Despite the obvious setbacks that we have experienced, I believe that we can succeed in bringing peace and stability to Iraq," he said. "It will help to achieve that goal if we're willing to learn from our mistakes. The first step is to recognize that mistakes were made."

Criticisms include: too few troops sent over in the first place; a lack of planning for postwar operations; unilateral action that has left the United States bearing the bulk of the financial and human toll; and overly optimistic predictions on what it would take to oust Saddam and build a new democratic government in his place.

Meanwhile, presidential press secretary Scott McClellan said President Bush invited congressional Republicans to a meeting at the White House late Tuesday.

McClellan said the "coalition is strong" in Iraq despite the announcements this week of the impending departure of troops from Spain and Honduras. Asked whether this was evidence the coalition was unraveling, McClellan, traveling with Bush to Buffalo, N.Y., replied, "I disagree with that strongly."

Worry about events in Iraq crosses party lines.

The hearings come during the deadliest month in Iraq for U.S. forces since the invasion began — 100 killed in the increasingly violent insurgency. Some estimate over 1,000 Iraqis have died, including civilians, insurgents and police.

Many lawmakers who visited their districts on the just-ended spring recess faced constituents' questions about Iraq.

Polls are showing an increase in the number of Americans who think troops should come home and a reduction in support for the president's handling of Iraq. Already, almost six in 10 of those surveyed say he does not have a clear plan for success in Iraq.

Republicans say Bush eased some Americans' concerns with his news conference last week when he pledged to stay the course in Iraq. Democrats say he was short on details.