Two Western states have become the first in the nation to legalize recreational marijuana use.

Yesterday, voters in Colorado and Washington passed initiatives to allow the possession and sale of pot for recreational use. Pro-legalization groups, such as NORML, hailed the votes as a victory, saying in a press release that “the significance of these events cannot be understated.” The Drug Policy Alliance said the outcome reflects increased national support for liberalized marijuana laws and cited a 2011 Gallup poll finding that half of Americans favored making pot legal.

Nonetheless, the federal government maintains that marijuana is an illegal drug, and experts say the battle over these states’ new initiatives could end up in court. “Once these states actually try to implement these laws, we will see an effort by the Feds to shut it down,” Kevin Sabet, a former senior adviser to the Obama administration’s Office of National Drug Control Policy, told NBC News.

Before the election, business leaders in Colorado voiced concerns about the marijuana initiative. Denver Mayer Michael Hancock, the head of the Denver Metro Chamber of Commerce and other organizations said legalizing pot would be bad for business in Colorado because it would discourage companies from moving to the state. “Becoming the marijuana capital of the country will not boost this progress,” Hancock said at a news conference. “It will only hurt it.”

But Colorado unions said the new marijuana measure would have the opposite effect. “Removing marijuana from the underground market … will create living-wage jobs and bolster our state and local economies with tens of millions of dollars in new tax revenue and savings,” local union president Kim Cordova told the Denver Post.

Colorado’s ballot initiative states that nothing in the measure “is intended to require an employer to permit or accommodate the use, consumption, possession, transfer, display, transportation, sale or growing on marijuana in the workplace or to affect the ability of employers to have policies restricting the use of marijuana by employees.” But some business leaders worry the marijuana measure will lead to lawsuits if employers fire employees over their marijuana use. The Mountain States Employers Council says the marijuana initiative is “coyly drafted to invite litigation.”

Read CNN and Reuters for more about Colorado and Washington’s new initiatives.

For more marijuana-related legal coverage from InsideCounsel, read:

Ex-Wal-Mart employee fired for medical marijuana use loses appeal

Labor: Employment protections under medical marijuana laws

Medical Marijuana Users Raise Unexpected Issues for Employers