When the Founding Fathers met in Philadelphia during the 1787 Constitutional Convention, they represented a loosely held confederacy of Atlantic states recently freed from British rule. If the American experiment was going to work, the founding fathers knew that they had to insulate their new republic from deep-pocketed interests and old alliances from Europe.

Through a course of heated conversations and compromises, safeguards against foreign influence as a corrupting force were built into the Constitution.

“The founders had just broken free from one empire, and the idea that some other empire was going to swallow them up was a constant source of fear for them,” says Mary Sarah Bilder, law professor and constitutional historian at Boston College Law School, and author of Madison’s Hand: Revising the Constitutional Convention.

American statesmen like Benjamin Franklin and Thomas Jefferson were no strangers to the backroom deals and soap-opera plot lines of 18th-century European politics. Gift-giving was common practice among foreign dignitaries, as was bestowing of titles of nobility on foreign political friends. Intermarriage of royal families was another classic way to bind the interests of two nations together.

If the United States was going to be different, the framers needed a founding document that fully recognized and defended against the corrupting influence of foreign money and power, particularly on the president.

“Article II of the Constitution gives such power to the president to run the executive branch that a president under the influence of a foreign nation would be far more dangerous than any other single individual,” says Stephen Saltzburg, professor at The George Washington University Law School. “That kind of conflict, between loyalty to the United States and loyalty to a foreign nation, would be intolerable.”

To guard against such conflicts and provide a remedy for a worst-case scenario of presidential corruption, the founders built two key provisions into the Constitution: the so-called “emoluments clause” and the power to impeach a president.

The emoluments clause is laid out in Article I, Section 9 of the Constitution: “And no Person holding any Office of Profit or Trust under them, shall, without the Consent of the Congress, accept of any present, Emolument, Office, or Title, of any kind whatever, from any King, Prince or foreign State.”

No gifts, no titles of nobility—the Constitution bars American presidents, ambassadors and elected representatives from even the appearance of quid pro quo. But several members of the Constitutional Convention argued this clause alone wasn’t enough to hedge against corruption of the highest office in the nation. Congress needed a remedy, a way to punish a president who crossed the line.

In James Madison’s notes from the Constitutional Convention, he says that Gouverneur Morris, author of the Preamble to the Constitution, didn’t originally see the necessity of impeachment until he considered the specter of foreign corruption.

“[The Executive] may be bribed by a greater interest to betray his trust; and no one would say that we ought to expose ourselves to the danger of seeing the first Magistrate in foreign pay without being able to guard against by displacing him,” said Morris. “One would think the King of England well secured against bribery. Yet Charles II was bribed by Louis XIV.”

In the 17 century, Charles II secretly accepted money from the power-hungry French King Louis XIV in exchange for selling off parts of England to France and publicly converting to Catholicism.

By including both the emoluments clause and congressional impeachment powers in the Constitution, the founders believed they had a two-pronged attack against foreign influence. As Edmund Jennings Randolph said at the Virginia Ratifying Convention in 1788, “It is impossible to guard better against corruption.”

In George Washington’s 1796 farewell address as the first president of the United States, he issued a stern warning against the poisonous influence of foreign governments on the affairs of the young nation.

"Against the insidious wiles of foreign influence... the jealousy of a free people ought to be constantly awake, since history and experience prove that foreign influence is one of the most baneful foes of republican government."

While Washington resisted foreign influence as president, the framers of the Constitution recognized that the possibility of a corruptible American president was real.

“In the words of the constitutional scholar Cecilia Kenyon, many of the founders were ‘men of little faith,’” says Bilder. “They fundamentally believed that people’s private ambitions and thirst for more power or money were powerful motivators. You couldn't rely on the goodness of human nature. In fact, you had to create these redundant structures to guard against it.”