WASHINGTON – President Bush will deliver the third in a series of speeches on the Iraq war today, four days ahead of parliamentary elections in that country that will mark a major test of Mr. Bush’s tough rhetoric over the past two weeks in the face of critics from both political parties.

A White House spokesman, Trent Duffy, said that Mr. Bush’s speech today before the World Affairs Council in Philadelphia will focus on the importance of helping Iraqis build the institutions they need to support a lasting democracy. In two other recent speeches on the war, Mr. Bush discussed training Iraqi security forces and economic reconstruction.

The speeches have emboldened Republicans in Congress and may have contributed to a small spike in the president’s popularity in the past week. An Associated Press-Ipsos poll released Friday showed Mr. Bush’s popularity at 42%, its highest level since the summer.

Mr. Bush’s general message has been to assure his audiences that the administration has a strategy for success and that it will not leave Iraq until the mission is complete. He has spoken in greater detail about victories in cities such as Mosul and Najaf, and talked about the type of enemy Americans in Iraq face. Mr. Bush has also blasted members of Congress who would have the administration set “an artificial timetable” for withdrawal.

On this week’s elections, Mr. Bush told students at the U.S. Naval Academy two weeks ago that he expects many of the minority Sunnis who boycotted last January’s election of an interim government to realize that a strong federal government provides their best guarantee of minority rights in a new Iraq. A high turnout could help boost Mr. Bush’s fortunes more and strengthen the hand of those who have called for patience.

Mr. Bush will be joined at today’s speech by Pennsylvania’s Republican senators, Arlen Specter and Rick Santorum. Mr. Santorum, the chairman of the Republican Leadership Conference, has urged administration officials to speak out on the war effort. A member of his leadership staff, who asked not to be identified, said Republicans are pleased not only with Mr. Bush’s message in the speeches but also the fact that he is giving them at all.

“We’ve seen now for the past year that the president kind of went away, and the people who opposed the war just kept talking and there was no comeback,” the staffer said. “We’re very glad to see the president being very aggressive in defending the war on terrorism and on protecting the U.S. We’ve been saying ‘get out there.’ In order to prosecute this war and to be able to make the case for what we’re doing, they need to be aggressive because the media certainly isn’t looking for reasons to support the war.”

This week’s elections are the first since Iraq ratified its constitution in October. The Bush Administration has increased troop levels to 160,000 from 137,000 in preparation for the elections and has warned voters who have turned out in increasingly strong numbers in three national elections that they can expect an uptick in violence this week. Voters will elect 275 members of parliament for four-year terms. The parliament will then choose a prime minister. The prime minister will form a Cabinet.

The president of the Center for Security Policy, Frank Gaffney, said Mr. Bush’s speeches have the effect of helping the domestic audience understand the war effort and the possible secondary effect of encouraging voters in Iraq to turn out in greater numbers out of a sense that America is committed to staying for the long haul. Mr. Gaffney is lead author of a recently published book: “War Footing: Ten Steps America Must Take to Prevail in the War for the Free World.”

“I’m very much a believer that the determinant of what will happen not just in these elections but more generally is going to be a product of whether the Iraqi people have confidence in their future – namely, a future that is different than their past and one that is likely to prove substantially better than the present. I think these speeches are conducive of that and necessary to contrast a lot of other signals that have been sent by a lot of other American politicians that almost certainly create uncertainty on their part about the future,” Mr. Gaffney said.