The lawsuit, filed earlier this month by six Democratic members of Congress and three unidentified service members and their parents, maintained that only Congress has the constitutional authority to declare war.
The plaintiffs argued that the resolution Congress approved in October supporting military action against Iraq did not specifically declare war and unlawfully ceded the decision to Mr. Bush.
One of the plaintiffs, Democratic Rep. John Conyers, cited the passage of the U.S. Constitution that states: "Congress shall have power ... to declare war."
However, U.S. District Judge Joseph Tauro ruled Monday that the court did not have jurisdiction to issue an injunction against Mr. Bush.
Tauro said the lawsuit engaged "political questions in the legal sense that are beyond the jurisdiction of the court."
The judge added that, considering the October congressional resolution, he could not find evidence of any conflict between the will of the executive and legislative branches.
"Case law makes clear that the Congress does not have the exclusive right to determine whether or not the United States engages in war," he said.
An attorney for the government, Joseph Hunt, had argued that the court had no standing to issue an injunction because there was no conflict between Congress and the president. Hunt said it was also premature for the court to become involved because no one could say whether war was truly imminent or whether the president was merely using the threat of war as a bluff.
Congress has not formally declared a war since World War II. The War Powers Act, passed in 1973 in response to the war in Vietnam and the actions of President Richard Nixon, requires the president to seek congressional approval before or shortly after ordering military action abroad. It also requires the president to report to Congress.
A similar lawsuit was filed against Mr. Bush's father before the Gulf War by 54 members of Congress but was rejected by a federal judge in 1990.
That judge said the elder President George Bush had not clearly committed the country to a course of action. The judge also noted that only about 10 percent of the Congress had asked for the injunction — a percentage he said was not representative of the entire body.