The major U.S. presidential candidates highlighted their positions on the Iraq war in high-profile Senate hearings that featured testimony from the top U.S. military commander in Iraq, General David Petraeus. Republican Senator John McCain and Democratic Senators Hillary Clinton and Barack Obama returned to Capitol Hill Tuesday to take part, as VOA's Deborah Tate reports from Capitol Hill.

The televised Senate hearings offered the presidential candidates a high-profile setting to discuss their views on the Iraq war, which many Americans now oppose.

Senators Hillary Clinton and Barack Obama, who are battling for the Democratic Party nomination for president, renewed their calls for a gradual withdrawal of U.S. troops from Iraq.

Senator Clinton made her comments at a Senate Armed Services Committee hearing.

"I think it is time to begin an orderly process of withdrawing our troops, start rebuilding our military and focusing on the challenges posed by Afghanistan, global terrorist groups and other problems that confront America," she said.

Senator Obama, speaking during a Senate Foreign Relations Committee hearing later in the day, said setting a timetable for a troop withdrawal would help increase the pressure on Iraqis to make necessary political compromises.

"Nobody is asking for a precipitous withdrawal, but I do think it has to be a measured, but increased pressure," he said.

Obama also called for a surge in diplomacy, including talks with Iran, in an effort to stabilize Iraq.

Obama was an early critic of the decision to invade Iraq. He has often noted that Senator Clinton had voted to authorize the war. He used his committee appearance to reiterate that he continues to believe the decision to go to war was a massive, strategic blunder.

In stark contrast to Senators Obama and Clinton, Senator John McCain warned against withdrawing U.S. troops before stability is established in Iraq.

 "The promise of withdrawal of our forces regardless of the consequences will constitute a failure of political and moral leadership," he said.

McCain, the top Republican on the Senate Armed Services Committee and his party's presumed presidential nominee, warned that a precipitous withdrawal could unleash sectarian tensions - leading to a full scale civil war that could destabilize the Middle East.