A Colorado Republican is asking the Justice Department if its decision not to challenge the implementation of marijuana legalization in his home state and Washington state means other federal laws will be undermined as well.

Federal prosecutors were advised last month in a DOJ memo to steer resources away from enforcing federal pot laws on the expectation that state and local authorities in the affected states will handle enforcement and keep the newly legal drug out of the hands of minors.

If the states fail to do this, or other violations aren’t dealt with such as cartels reaping revenue from sales or growing on public land, then the feds reserve the right to step in.

“I write to question the Department’s constitutional authority on overriding federal law and seek answers as to whether this action sets precedent to allow states to opt out of other federal laws,” Rep. Cory Gardner (R-Colo.) wrote in a letter to Attorney General Eric Holder.

“While I commend the DOJ for finally issuing guidance after nearly ten months since Colorado voters legalized marijuana’s recreation use, its new policies are in contrast to the Controlled Substances Act. Essentially, DOJ policy now allows states like Colorado to opt out of federal marijuana laws. Do you believe the DOJ has the authority to override federal law? Do you believe you have the authority to change law without the approval of Congress?” Gardner continued.

Gardner wrote President Obama in June, asking him to explain the administration’s unilateral actions in several areas including not upholding federal drug laws.

“I have yet to receive a response, and I still question the constitutionality of this administration overriding federal law,” the congressman said.

“The new DOJ policies seem to imply that federal authorities will not preempt state laws. Does this set a precedent for other areas? For example, several states have passed laws to opt out of the Patient Protection and Affordable Care Act, yet the federal government has consistently said it will take over health insurance industries regardless of states that contest the law,” he added. “If you do not agree that there is a precedent set, would you explain the inconsistencies of why in certain areas federal law may be deemed irrelevant, but not in others?”