A Republican senator on Tuesday challenged George W. Bush's assertion that the U.S. president is the "decider" when it comes to war strategies, saying the responsibility is shared among lawmakers.

"I would suggest respectfully to the president that he is not the sole decider," said Arlen Specter during a hearing on the war powers of Congress. "The decider is a shared and joint responsibility."

Republican Senator Arlen Specter questioned whether U.S. President George W. Bush was the sole decider on the U.S. strategy in Iraq.
(Haraz N. Ghanbari/Associated Press)

Bush made the comment last April while defending former defence secretary Donald Rumsfeld, who was being criticized for his war strategy in Iraq.

At the time, Bush said: "I hear the voices, and I read the front page and I know the speculation. I'm the decider, and I decide what is best."

Rumsfeld resigned in November after the U.S. mid-term elections, which saw the Democrats take control of Congress for the first time in more than 10 years.

Now Democrats are considering whether to cut funding for the Iraq war, including for Bush's plan to send an extra 21,500 troops to the country. Vice-President Dick Cheney has challenged Congress to follow through on its objections to Bush's plan by cutting the war budget.

However, Democrats could face a high political price if they cancel war funding, fearing they'll be viewed as punishing soldiers.

The party could, however, set a cap on how many troops the U.S. can deploy to Iraq or set an end date for the war, which has already cost an estimated $350 billion US.

Congress used its war powers to cut off or put conditions on funding for the Vietnam War and conflicts in Cambodia, Somalia and Bosnia.

The U.S. Constitution says lawmakers can declare and fund wars, but the president controls military forces.

"The Constitution makes Congress a coequal branch of government. It's time we start acting like it," said Democratic Senator Russell Feingold.

But presidents also can veto legislation and Bush likely has enough support in Congress on Iraq to withstand any veto override attempts.

With files from the Associated Press