WASHINGTON — Senior White House and Justice Department officials are considering plans for legal action against Colorado and Washington that could undermine voter-approved initiatives to legalize the recreational use of marijuana in those states, according to several people familiar with the deliberations.

Even as marijuana legalization supporters are celebrating their victories in the two states, the Obama administration has been holding high-level meetings since the election to debate the response of federal law enforcement agencies to the decriminalization efforts.

Marijuana use in both states continues to be illegal under the federal Controlled Substances Act. One option is to sue the states on the grounds that any effort to regulate marijuana is pre-empted by federal law. Should the Justice Department prevail, it would raise the possibility of striking down the entire initiatives on the theory that voters would not have approved legalizing the drug without tight regulations and licensing similar to controls on hard alcohol.

Some law enforcement officials, alarmed at the prospect that marijuana users in both states could get used to flouting federal law openly, are said to be pushing for a stern response. But such a response would raise political complications for President Obama because marijuana legalization is popular among liberal Democrats who just turned out to re-elect him.