President Trump declared a national emergency with the express goal of circumventing Congress's constitutional power of the purse and getting more than the $1.375 billion that lawmakers were willing to give him for his wall.

But even Trump's declaration of an emergency does not hand him the keys to an unlimited slush fund. Indeed, as Roll Call explained on Thursday night, Trump will still need congressional approval to access as much as one-third of the funds that he had planned on using for the wall. For example, the Trump administration had planned to pull some $2.5 billion from Pentagon counterdrug funds. Although Trump is allowed to use that money under federal law, he can only spend money that’s actually in the account and, right now, there’s only $85 million there.

To make up the difference, the Defense Department is likely to try to reprogram money to the counterdrug fund, which could then be immediately pulled and used for the wall. But any attempt to reprogram the funds would run headlong into Congress.

That leaves Trump right back where he started — needing Congress to give him money for his wall.

Congress should not play along, lest it lend implicit approval to a president’s desire to simply cut Congress out of the picture when he doesn’t get what he wants. The wall's merits aside, no lawmaker of any party should support the president’s efforts to override Congress by freely transferring funds for him to plunder. In fact, far from bending over backwards to meet the president's will, Congress should be working to take back the power that it has previously ceded to the executive.