Republican senators -- joined by at least one Democrat -- ripped the international arms trade treaty approved Tuesday by the U.N. General Assembly, calling it a "non-starter" and vowing to oppose Senate ratification.
The treaty approved Tuesday was the first of its kind. The resolution was approved at the U.N. by a vote of 154 to 3 with 23 abstentions.
But in the U.S. Senate, which must ratify the treaty in order for the United States to be a party to it, opposition is much stronger.
The Senate already voted for an amendment last month to prevent the U.S. from entering into the treaty. The sentiment among conservative and moderate senators concerned the treaty represents an infringement of Second Amendment rights had not changed in light of Tuesday's U.N. vote.
"The U.N. Arms Trade Treaty that passed in the General Assembly today would require the United States to implement gun-control legislation as required by the treaty, which could supersede the laws our elected officials have already put into place," Sen. James Inhofe, R-Okla., said in a statement. "It's time the Obama administration recognizes it is already a non-starter, and Americans will not stand for internationalists limiting and infringing upon their Constitutional rights."
Democratic Sen. Max Baucus, of Montana, also said he could not support the treaty, claiming it doesn't do enough to "uphold the rights of Americans."
Critics of the treaty claim that, while it's aimed at combating the vast illegal weapons trade, it could end up burdening law-abiding gun owners and businesses with a new web of red tape. Inhofe also said the treaty could hurt national security efforts by preventing the U.S. from assisting allies.
What impact it will have in curbing the estimated $60 billion global arms trade remains to be seen. The landmark U.N. treaty will take effect after 50 countries ratify it, and a lot will depend on which ones ratify and which ones don't, and how stringently it is implemented.
In the U.S. Senate, it takes two-thirds of the 100 lawmakers to win ratification.
Enforcement is left up to the nations that ratify the treaty. The treaty requires these countries to cooperate on its implementation and to assist each other in investigating and prosecuting violations.
Britain and a small group of other treaty supporters sought a vote in the 193-member world body after Iran, North Korea and Syria blocked its adoption by consensus last week. The three countries voted "no" on Tuesday, while Russia and China, both major arms exporters, abstained. The United States, the world's largest arms exporter, voted in favor.
Secretary of State John Kerry welcomed the approval of "a strong, effective and implementable arms trade treaty that can strengthen global security while protecting the sovereign right of states to conduct legitimate arms trade." He stressed that the treaty applies only to international trade "and reaffirms the sovereign right of any state to regulate arms within its territory."
White House Press Secretary Jay Carney said the administration was "pleased" by the outcome.
But Texas Attorney General Greg Abbott swiftly fired off a letter to Obama Tuesday urging him not to sign it. He threatened that if the treaty were eventually signed and ratified, his state would "lead the charge" to have it overturned in court "as a violation of the U.S. Constitution."
He voiced concern that the treaty "empowers a new U.N. bureaucracy focused on firearms restrictions that will be run by international bureaucrats."
Never before has there been an international treaty regulating the global arms trade. Supporters said its adoption took far too long.
Australian Ambassador Peter Woolcott, who chaired the negotiations, said the treaty will "make an important difference by reducing human suffering and saving lives."
"We owe it to those millions -- often the most vulnerable in society -- whose lives have been overshadowed by the irresponsible and illicit international trade in arms," he told the assembly just before the vote.
The treaty will not control the domestic use of weapons in any country, but it will require countries that ratify it to establish national regulations to control the transfer of conventional arms and components and to regulate arms brokers.
It covers battle tanks, armored combat vehicles, large-caliber artillery systems, combat aircraft, attack helicopters, warships, missiles and missile launchers, and small arms and light weapons. A phrase stating that the treaty covers these weapons "at a minimum" was dropped, according to diplomats, at the insistence of the United States. Supporters complained that this limited the treaty's scope.
The treaty prohibits states that ratify it from transferring conventional weapons if they violate arms embargoes or if they promote acts of genocide, crimes against humanity or war crimes. The pact also prohibits the export of conventional arms if they could be used in attacks on civilians or civilian buildings such as schools and hospitals.
In considering whether to authorize the export of arms, a country must evaluate whether the weapons would be used to violate international human rights laws or employed by terrorists or organized crime. A country must also determine whether the weapons would contribute to or undermine peace and security.
In addition, the treaty requires countries to take measures to prevent the diversion of conventional weapons to the illicit market.
Proponents of the treaty said it could make it much harder for regimes committing human rights violations to acquire arms, in conflicts such as the brutal civil war in Syria.
The Associated Press contributed to this report.