President Barack Obama warned Congress this afternoon that he considers numerous provisions of the megabus spending bill to be unconstitutional, including provisions relating to detainees held at Guantánamo Bay, Cuba.

“My Administration has repeatedly communicated my objections to these provisions, including my view that they could, under certain circumstances, violate constitutional separation of powers principles,” Obama wrote in a signing statement today as he departed for his family vacation in Hawaii. “In approving this bill, I reiterate the objections my Administration has raised regarding these provisions, my intent to interpret and apply them in a manner that avoids constitutional conflicts, and the promise that my Administration will continue to work towards their repeal.”

Obama also said several other provisions interfere with his constitutional authority, including a provision requiring him to notify Congress of military exercises costing more than $100,000, as well as a limitation on placing U.S. soldiers in United Nations peacekeeping roles under a foreign commander.

“I will apply these provisions in a manner consistent with my constitutional authority as Commander in Chief,” Obama wrote.

Several other provisions involving foreign relations and related to Obama’s own advisers also will be effectively ignored.