Attorney General Jeff Sessions has managed to undo a longstanding Obama-era policy and break one of President Donald Trump's promises while adding to the uncertainty already plaguing the burgeoning recreational marijuana industry in eight states and the District of Columbia.

Sessions on Thursday rescinded several directives issued during the Obama administration that discouraged federal prosecutors from pursuing marijuana cases in states that had legalized its use. The attorney general was reaffirming his own opposition to marijuana legalization, despite Trump's declaration during the presidential campaign that the issue should be left up to the states.

Republicans are fond of touting "state's rights" to defend local initiatives against what they see as federal government overreach. In this case, apparently fear trumped principle. Oregon Sen. Ron Wyden said in a statement, "Once again the Trump administration is doubling down on protecting states’ rights only when they believe the state is right."

Republican Sen. Cory Gardner of Colorado said Sessions' actions contradicted a statement he made before his confirmation, and Gardner vowed to block Justice Department nominations in retaliation.

Marijuana remains illegal under federal law, although states such as Oregon had proceeded with legalization with the understanding that the Justice Department would take a hands-off approach as long as state officials did everything they could to stamp out the black market. Now that tenuous arrangement is even more precarious.

Not only is the principle of federalism being violated, a rapidly growing industry and the jobs it is creating are threatened as well.