The House of Representatives has voted down a measure that would have granted congressional consent for American involvement in military action in Libya.
But the House also rejected a subsequent bill, which threatened to halt US air strikes in the embattled country by cutting off funds for military operations.
Secretary of State Hillary Clinton welcomed the House's decision not to cut the funding.
"We are gratified that the House has decisively rejected efforts to limit funding for the Libyan mission," Clinton told reporters at the State Department.
While the first vote is unlikely to affect US involvement in the NATO-led campaign, the rejection of congressional approval represents a symbolic blow to US President Barack Obama.
The first vote on Friday saw 295 representatives - mostly Republicans - oppose the measure, brought by Obama's Democratic allies, while 123 voted in favour.
About 70 Democrats broke with Obama to defeat the measure, and just eight Republicans backed the resolution.
The second bill received 180 votes in favour and 238 against, with 89 Republicans joining Democrats to oppose the bill.
Members of both parties angrily denounced Obama's decision not to seek permission for the US role in Libya as required under the 1973 War Powers Act, which names congress as the only body legally able to declare war.
"The president is becoming an absolute monarch, and we must put a stop to that right now if we don't want to become an empire instead of a republic," said Jerrold Nadler, a Democratic representative, as debate opened.
A decade ago, then-US president George W Bush ignored the War Powers Act at the beginning of the NATO-backed US invasion of Afghanistan, but representatives now face a US public frustrated by a massive debt crisis and a decade of overseas conflicts in Afghanistan in Iraq.
Some Democrats accused Republicans of playing politics with national security.
"I, myself, believe the president has the latitude to do what he is doing as long as there are no boots on the ground," Nancy Pelosi, the leader of the Democratic congressional minority, told reporters.
But, she added, "I also always say that consultation strengthens the resolve of our country, and the more consultation the better."
Al Jazeera's Patty Culhane said that the votes were really a question about the power of the presidency, and were more of a "congressional stab" at Obama.
"For those on the ground in Libya, do not expect to see an end to drone [or other] strikes," she said.
US lawmakers in both the House and the Senate have been harsher on Democratic presidents than Republican presidents in recent decades, and Friday's vote marked the first time since 1999 that either US government chamber had voted against a military operation.
The last time was over then-president Bill Clinton's authority in the war in Kosovo.
When Bush asked for approval to use government funds for the war in Afghanistan, a small group of congressional representatives voted against the measure.
Throughout the rest of Bush's tenure, Democratic representatives introduced measures to stop war funding as well as articles of impeachment, but none got far in the legislative chambers.