Republicans have justifiably criticized President Obama for skirting the constitutional need to obtain legislation for his agenda in issues from climate change to immigration to health care. Although some of this condemnation is political—because Obama has issued fewer executive orders since Grover Cleveland in the late 1800s—Obama is almost certain to take more unilateral executive action late in his presidency when he is likely to be less effective with Congress. However, such unconstitutional practice has to stop. Executive orders are usually fine when the president is merely implementing congressional legislation, but the Constitution does not allow a president to use them “when Congress fails to act”—as Obama and other presidents have claimed. The Constitution does not provide legislative powers to the president.

Yet an even worse problem with executive aggrandizement exists in foreign policy and national security. Presidents somehow got the idea that they are the “sole organ” of U.S. policy abroad—beginning with the non-binding aspect of a Supreme Court ruling in the 1930s. However, even if the Supreme Court had formally endorsed this principle, it wouldn’t be constitutional.

American policymakers and the public need to pull out a copy of the Constitution and read it. If they did, they would find—contrary to the strutting and flexing of many recent chief executives—that the document gives most of the powers in foreign affairs and national security to the Congress. Because in the course of the republic’s history, the modified parliamentary system intended by the Constitution’s framers has been severely warped into a presidential-heavy separation of powers arrangement, the chief executive has usurped some of the legislative branch’s most important powers in foreign policy and national security.

Article I of the Constitution (the order of the articles is very telling about what the framers intended about the relative importance of various government branches) provides a long list of congressional powers in foreign affairs and to “provide for the common defense,” including declaring war and approval of lesser armed conflict; providing funds to raise and support armies and to maintain a navy; regulating those armed forces; organizing, arming, and disciplining the militia and calling it forth to resist invasion, enforce domestic law, and suppress insurrections; regulating commerce with foreign nations; and establishing rules for foreign immigration.

The much shorter Article II, governing executive powers, gives the president the sole powers only to receive foreign ambassadors and to act as the commander-in-chief of the U.S. armed forces and militia. The president has the power to make treaties with foreign countries and appoint U.S. ambassadors to them—but only with two-thirds approval of the Senate.

However, over the course of U.S. history, executives have usurped congressional authority and expanded their short list of powers —now claiming the right to conduct U.S. foreign and national security policy with only perfunctory consultation with Congress. For example, the president often takes the country to war without any congressional approval and has usurped substantial congressional power in the budgeting process. As noted earlier, the executive has been eroding Congress’s role in regulating immigration.

In expanding executive powers, the president has vastly augmented his role as commander-in-chief—from the narrow battlefield role intended by the framers into nearly the role of commander-in-chief of the nation. For example, after 9/11, as commander-in-chief, George W. Bush effectively suspended habeas corpus, the constitutional right of prisoners to challenge their detention by the government; yet the Constitution places the power of such suspension in Article I under congressional authority and then only in times of rebellion or invasion (9/11 was neither).

But how does expanding executive power affect any potential final agreement with Iran to limit its nuclear program? Presidents, starting at least as far back as the 1840s with John Tyler, have tried to avoid the requirement for a two-thirds vote of the Senate on treaties by reaching “executive agreements” with foreign nations. Some of these agreements have been approved by majority votes of both the Senate and House of Representatives and some have not received any congressional approval at all. Yet the Constitution does not mention presidential authority to make such agreements, because they circumvent the requirement for overwhelming Senatorial approval of important arrangements with foreign countries. Unfortunately, Obama administration officials have talked about going this unconstitutional route on any final settlement with Iran.

In addition, any final agreement with Iran would likely require the lifting of congressionally imposed economic sanctions. Administration officials are talking about delaying for years the need for such congressional action by suspending or waiving some sanctions by executive order. Congress allowing the executive to do so is also questionable constitutionally.

There are few people who want a deal between the United States and Iran over its nuclear program more than I do. Such a pact would laudably nix any likely ineffectual and counterproductive military action against Iran. But even an important deal with a foreign country needs to pass muster with blueprint of the republic. To be constitutional, any agreement with Iran must be in the form of a treaty, which would need to be ratified by two-thirds of the Senate.