When President Trump took the oath of office, he swore to “preserve, protect and defend” the Constitution of the United States. Yet since he took that oath, he has been flagrantly violating a critical provision of the Constitution that was designed to ensure that the nation’s leaders would always put the national interest above their personal self-interest.

Today, Senator Richard Blumenthal, Representative John Conyers, and 194 other members of Congress have gone to federal court seeking to put an end to the President’s willful violations of the Constitution. We, at the Constitutional Accountability Center, are proud to represent them in this effort.

When the nation’s Founders came together to draft a new national charter, they were profoundly concerned about both corruption of federal officeholders and foreign influence over the nation. They understood what a threat corruption posed, and they worried that foreign nations might attempt to meddle in America’s affairs, including by giving benefits to the nation’s chief executive to subvert his loyalties.

In response to those concerns, the Founders included in the Constitution the Foreign Emoluments Clause, which prohibits any person “holding any Office of Profit or Trust under [the United States]” from “accept[ing] . . . any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince, or foreign State” without “the consent of the Congress.” Although there’s been a great deal of talk about this Clause since Donald Trump’s election, there has been much less talk about five of its most important words: “the consent of the Congress.”

To the Founders, “the consent of the Congress” language was critical. By requiring federal officeholders to first go to Congress and identify the specific benefits they wished to accept from foreign states, the Founders ensured that an officeholder would not be the sole judge of his own integrity.

Moreover, and just as important, they also ensured that a federal officeholder’s acceptance of any foreign “Emolument[s]” would be transparent and subject to public examination, thus minimizing the dangers of corruption and influence that the Foreign Emoluments Clause was adopted to prevent. When Congress was first called upon to exercise this responsibility in 1798, one lawmaker explained its value in this fashion: “[i]f presents were allowed to be received without number, and privately, they might produce an improper effect, by seducing men from an honest attachment for their country, in favor of that which was loading them with favors.”

Historically, presidents have respected their obligations under the Foreign Emoluments Clause and have declined to accept presents or emoluments from foreign states without obtaining the consent of Congress. Yet President Trump hasn’t done what previous presidents have done. Even though public reports indicate that he or his businesses have been accepting benefits from foreign states since his inauguration, he has never gone to Congress, identified those benefits, and asked the members of Congress for their consent. It is known, for example, that foreign governments have granted Trump preliminary approval of trademarks that could be worth millions of dollars, and that they are paying for rooms and events at Trump hotels, and to lease space at Trump properties.

And while what is known is more than enough to show that the President has been violating the Constitution, there’s a great deal that is not known. Indeed, there’s a great deal that Americans can’t know, given the President’s general lack of transparency and his unwillingness to go to Congress. Again, the Framers permitted federal officeholders to accept benefits from foreign states with the consent of Congress because they believed that disclosure of the specific benefits officeholders wanted to accept would ensure accountability and transparency. By refusing to seek the consent of Congress as the Constitution requires, President Trump is denying the American people the transparency that critical language was adopted to provide.

And President Trump’s failure to comply with the Constitution matters. The Founders included the Foreign Emoluments Clause in the Constitution because they recognized that the American people would be hurt if federal officeholders, and especially the President, made policy decisions based on their own self-interest rather than the national interest. As President Trump addresses critical trade issues with China, as he decides where to send U.S. troops and how to allocate U.S. resources, and as he makes significant foreign policy decisions, the American people cannot know whether is he acting in their best interest or in his own.

In short, by failing to go to Congress and seek its consent, the President willfully violates an important provision of our nation’s highest law. By failing to go to Congress and seek its consent, he harms the American people, forcing them to ask whether the President of the United States is motivated by the public interest or his own financial interest. And by failing to go to Congress and seek its consent, he denies members of Congress an opportunity to which they are entitled under the Constitution—to give or withhold their consent to his acceptance of these benefits from foreign states.

President Trump could have complied with the Constitution. But because he has chosen not to, members of Congress have no choice but to ask the courts to require him to do so.