A proposed constitutional amendment to allow Congress to ban the desecration of the US flag has been narrowly defeated in the US Senate.
Flag burning was upheld under freedom of speech in 1989
The 66-34 tally was just one vote short of the two-thirds majority needed.
The vote is part of a series planned by Republicans on key issues ahead of November's mid-term elections.
The ban's backers argued the flag was a cherished symbol needing protection while opponents warned against tampering with freedom of speech.
"Countless men and women have died defending that flag. It is but a small humble act for us to defend it," Senate Majority Leader Bill Frist said at the end of two days of debate.
At a time of war, he said, it was important to protect the flag as a symbol of freedom and national unity.
But opponents, who included 30 Democrats and three Republicans, said a constitutional amendment would violate the First Amendment right to free speech.
"While I take offence at disrespect to the flag, I nonetheless believe it is my continued duty as a veteran, as an American citizen, and as a United States senator to defend the constitutional right of protesters to use the flag in non-violent speech," said Sen Daniel Inouye, a World War II veteran.
There have been regular votes in the US Congress on outlawing desecration since the US Supreme Court ruled in 1989 and 1990 that burning the Stars and Stripes was an example of free speech and protected by the American constitution.
Tuesday's vote was the closest that supporters of a constitutional amendment - on this occasion 52 Republicans and 14 Democrats - have come to winning the argument.
Sponsored by Sen Orrin Hatch, the amendment read: "The Congress shall have power to prohibit the physical desecration of the flag of the United States."
Just one more senator on board and a ban on the proposed amendment would have been sent to individual states for ratification - a very rare occurrence.
There have been four recorded acts of flag burning in the United States this year, and 13 in 2005, according to the Citizens Flag Alliance, an association of veterans' groups which supported the amendment.
Democratic opponents dismissed the vote as the latest attempt by Republicans to appeal to their conservative base ahead of November's mid-term elections by painting those who voted against the bill as unpatriotic.
Those backing the measure earned the praise of President George W Bush, who said he continued to believe that the American people deserved the opportunity to express their views on this important issue.