The US Senate Thursday voted down a Republican-led effort to strip President Barack Obama of the ability to regulate greenhouse-gas emissions blamed for global warming.
But the narrow 53-47 vote, which attracted the support of some prominent Democrats, sent a signal to Obama over how difficult it will be to get major climate and energy reforms through Congress.
The Senate resolution would have overturned a so-called "endangerment finding" by the Environmental Protection Agency (EPA), the US regulator which last year ruled that greenhouse-gases posed a danger to US public health and environment.
The controversial ruling gave the EPA authority to regulate greenhouse-gas emissions under a previous clean-air law passed in 1990. Republicans, joined by some Democrats, argued this constituted gross overreach by a government agency.
Obama has said he would prefer Congress to pass a new law that specifically regulates heat-trapping gases that are warming the planet. But he has reserved the right to use the EPA's self-declared authority if Congress fails to act.
A comprehensive bill that would lower US emissions by forcing US companies to pay for their pollution faces an uphill battle in the Senate, with most Republicans opposed and many Democrats from energy-intensive states fearful of its effects on a struggling economy.