The US House of Representatives has approved a constitutional amendment allowing lawmakers to ban flag burning.
Flag desecration is a sensitive issue in the US
The Republican-led House voted 286-130 on the divisive measure, which now goes before the Senate.
Similar moves in the past have failed to gather the two-thirds majority required for constitutional amendments in both houses of the US Congress.
The draft amendment aims to override a 1989 Supreme Court ruling protecting flag desecration as free speech.
The issue has been a rallying cause for conservatives ever since.
It gathered political momentum in the wake of the 11 September 2001 attacks on the US.
"Ask the men and women who stood on top of the World Trade Center," said Republican Randy Cunningham, a Californian congressman.
"Ask them and they will tell you - pass this amendment"
Wednesday's vote was the fifth time the Republican-dominated House has approved the amendment.
But so far it has failed to get the required 67 votes needed in the Senate.
However Democrats are divided on the issue, and recent changes in the Senate mean the measure could be approved.
"There are too many scenarios where we would lose," Terri Ann Schroeder of the American Civil Liberties Union - which opposes the amendment - told the New York Times.
The move does not directly prohibit desecration of the flag - but allows individual state legislatures and the US Congress to enact such a ban.
If the Senate in turn approves the amendment by a two-thirds majority, it still has to be ratified by 38 states.
The constitution has been amended 27 times, including the first 10 amendments known as the Bill of Rights.