In 2011, I took control of the Senate floor, over the objection of the leaders of both parties, to stand for a principle I believe is one of the most important in my job as U.S. Senator.

I stood up to demand that the President of the United States follow the constitution and come to Congress if he wanted to commit the United States to military action in Libya.

It was clear to me at the time that the situation was fraught with peril. It was clear to me at the time that the President did not understand the potential consequences of his actions, both in terms of the war itself in Libya, and in terms of the damage he was doing to the separation of powers in our government.

I used President Obama’s own words from 2007 to describe exactly what should happen and why it was important. I remembered them from back then because it was one of the things I liked about candidate Obama: a reluctance for war and a seeming respect for the powers of Congress to declare War.

In 2007 President Obama said, “The President does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation.”

As Commander-in-Chief, the President does have a duty to protect and defend the United States. In instances of self-defense, the President would be within his constitutional authority to act before advising Congress or seeking its consent. History has shown us time and again, however, that military action is most successful when it is authorized and supported by the Legislative branch. It is always preferable to have the informed consent of Congress prior to any military action

If only the President in 2011 had heeded my warning, or that of candidate Obama from 2007, he wouldn’t have made the appearance he made this past Sunday, explaining that Libya was his worst mistake as President.

President Obama on Fox News Sunday admitted he did not have a proper plan and did not think through the consequences of his illegal Libyan actions. The President said, “Probably failing to plan for the day after what I think was the right thing to do in intervening in Libya.”

Libya has now devolved into a failed state, a chaotic area where ISIS controls one-third of the country. The failure wasn’t simply in not planning ahead, but in naively believing we could topple a secular dictator and replace him with a Jeffersonian Democracy.

My point to the President is the same now as it was in 2011: your mistake was in not coming to Congress.

Congressional debate is a check and balance that hopefully prevents rash and ill-thought out war. There is a reason why the power to declare war is constitutionally that of the legislative branch and not the executive. It was deliberate and deliberated by our founding fathers.

As Madison said, “The constitution supposes, what the History of all Governments demonstrates, that the Executive is the branch of power most interested in war, and most prone to it. It has accordingly with studied care vested the question of war to the Legislature.”

The President was too rash in going to war in Libya in 2011. What would have solved this problem is not necessarily a better “plan” by the President, but rather, using the plan set forth in wisdom by our founding fathers, that he come to Congress to decide if we go to war.

Congress moves slower than the President, by design. That’s why in times of imminent danger the President may act unilaterally to defend our country.

This was not the case in Libya. What the President needed was deliberation, arguments on both sides, and a full examination of the costs and consequences of going to war, something I fought for and Congress could have provided.

Let’s hope he and others can learn from this moment. Let’s not have another President coming to us in the coming years with his regrets. Let’s follow the constitution and restore the power of Congress to declare war.