President Bush has hit back at critics of his revised plan for Iraq, which includes sending 21,500 extra troops.
Mr Bush challenged opponents for ideas, not just criticism
In his weekly radio address Mr Bush said members of Congress had a right to their views, but to oppose everything and propose nothing was irresponsible.
Mr Bush's revised plan was condemned by Democrats and some Republicans as a dangerous escalation of the conflict.
The president's comments came as the US Secretary of State held talks in Israel at the start of a Middle East tour.
The BBC's Katya Adler, in Jerusalem, says Condoleezza Rice's tour is aimed at winning Arab support for President Bush's new strategy in Iraq.
But many leaders want more US engagement in the Israeli-Palestinian conflict in exchange for their backing, our correspondent adds.
In his radio address, Mr Bush challenged Congress to come up with a better plan than his, in which the Iraqi security forces are meant to take the lead in tackling the conflict.
"Our brave troops should not have to wonder if their leaders in Washington will give them what they need," he said.
"I urge members of Congress to fulfil their responsibilities - make their views known - and always support our men and women in harm's way."
Earlier this week, Democratic Senator Joseph Biden called the revised White House strategy a "tragic mistake".
Republican Senator Chuck Hagel, a Vietnam War veteran, described it as "the most dangerous foreign policy blunder in this country since Vietnam".
Meanwhile, Ms Rice had talks in Jerusalem as she began renewed efforts to revive stalled negotiations between Israelis and Palestinians.
Ms Rice will also visit Arab capitals to rally support for the president's Iraq strategy. She warned that the US would oppose any Iranian or Syrian interference in Iraq.
Speaking at a joint news conference with the Israeli Foreign Minister, Tzipi Livni, Ms Rice said they were discussing how to push forward the international peace plan for the Middle East, known as the roadmap.
"It is a time when extremist forces are attempting to make it impossible to have the kind of Middle East in which Israelis and Palestinians and other people of the Middle East can live in peace, and in which democracy can make progress," Ms Rice said.
She will also be seeing President Mahmoud Abbas on Sunday and the Israeli Prime Minister, Ehud Olmert, on Monday.
Ms Rice has played down any hopes of a major breakthrough, stressing that she had not come to the region with a plan to end the conflict.
As well as Israel and the Palestinian territories, Ms Rice's week-long tour will take in Egypt, Jordan, Saudi Arabia and Kuwait.
Ms Rice has said Arab leaders have every incentive to help as a stable Iraq is also in their interests.
Ms Rice insists the US must stand firm over Iraqi security
Both President Bush and Ms Rice have said this week that they intend to step up measures against those threatening to destabilise Iraq.
She insisted that the US was not going to let either Iran or Syria continue activities that endangered American soldiers in Iraq.
"I don't think there is a government in the world that would sit by and let the Iranians in particular run networks inside Iraq that are building explosive devices of a very high quality that are being used to kill their soldiers.
"That's not an escalation, that's just good policy," Ms Rice told the BBC.