NEWPORT, R.I. — President Bush held up Israel as a model for defining success in Iraq, saying yesterday that the goal of America’s mission in Iraq is not eliminating attacks but enabling a democracy that can function despite continuing violence.

With his Iraq policies under increasing fire from the American public and lawmakers from both parties, Mr. Bush went to the U.S. Naval War College here to declare progress. As the president pleaded for patience, his top national security aide went to Capitol Hill to meet with a key Republican critic.

Senator Lugar of Indiana, the senior Republican on the Foreign Relations Committee, delivered a lengthy floor speech earlier this week contending that Mr. Bush’s war strategy won’t have time to work and that American troops should start leaving now.

The White House thought it had until an expected September assessment by military commanders to deal with political fallout on the unpopular war.

But criticism is mounting now. A majority of senators now believes that troops should start coming home within the next few months. And House Republicans are calling to revive the independent Iraq Study Group to give the nation new options.

Mr. Bush sought in his speech to put the brakes on these efforts. He said success in Iraq would usher in “a dawn of a Middle East where leaders are at peace with their own people, where children enjoy the opportunities their parents only dreamed of, and where America has new allies in the cause of freedom.”

He characterized the fight in Iraq, where tensions between Shiite and Sunni factions have kept the country in a cycle of violence, as primarily one against Al Qaeda forces and their use of grisly suicide attacks and car bombings to sow chaos and despair.

“They understand that sensational images are the best way to overwhelm the quiet progress on the ground,” Mr. Bush said.

But he laid out in some of his plainest terms yet how to define when the U.S. presence in Iraq has achieved its goals.

“Our success in Iraq must not be measured by the enemy’s ability to get a car bombing in the evening news,” he said. “No matter how good the security, terrorists will always be able to explode a bomb on a crowded street.”

He suggested Israel as a model.

There, Mr. Bush said, “Terrorists have taken innocent human life for years in suicide attacks. The difference is that Israel is a functioning democracy and it’s not prevented from carrying out its responsibilities. And that’s a good indicator of success that we’re looking for in Iraq.”

It was likely to be controversial — and possibly even explosive — for Mr. Bush to set out Israel as a model for a Muslim Middle Eastern nation. Israel has been locked for decades in an intractable dispute with Palestinian Arabs over territory, a conflict that is viewed as a major recruiting tool for Islamic extremist groups like Al Qaeda.

What America is aiming for in Iraq, Mr. Bush said, is “the rise of a government that can protect its people, deliver basic services for all its citizens and function as a democracy even amid violence.”

The president ordered 21,500 additional American combat troops to Iraq in January, as an effort to increase security in Baghdad and nearby Anbar province to a level that would allow political reconciliation and progress. With those troops finally all deployed, Mr. Bush yesterday ticked through the details of operations in several areas, declaring with the aid of maps and charts on screens that flanked him that progress already is being made in many places.

He said sectarian murders, after spiking up in May, are now down substantially from January levels. Car bombings and suicide attacks continue, but are down in May and June. He cited “astonishing signs of normalcy ” such as soccer matches and crowded markets.

“We got them there, and now we’re beginning to move, and there are hopeful signs,” Mr. Bush said.