President Trump and Russian President Vladimir Putin during their joint news conference Monday at the Presidential Palace in Helsinki. (Pablo Martinez Monsivais/Associated Press)
Gail Savage is a professor of history at St. Mary's College of Maryland, specializing in modern Britain.

On Monday, President Trump met with Russian President Vladimir Putin — then promptly sided with him. The meeting marked the culmination of two years of growing concern about Russian interference in the 2016 election and mounting fears that Russia is shaping U.S. foreign policy under Trump.

Fear of foreign interference in American affairs drove the Founders to place certain safeguards in the Constitution, including the now-famous emoluments clause. Trump’s behavior serves not just as a reminder of why those safeguards are necessary, but also as a reminder of the British king who inspired them: Charles II. Charles’s political acumen and maneuvering link the 17th century past with the 21st century present, links that go through the debates that shaped the Constitution and its barriers to foreign meddling.

In 1660, Charles brought the monarchy back to England after the collapse of the Cromwellian Commonwealth, a brief period of republican rule that ended shortly after Oliver Cromwell’s death in 1658. Cromwell — victorious leader of Parliamentarian forces in the 1642-1651 Civil War between the crown, held by Charles I, and Parliament — failed to devise a satisfactory alternative to a mixed monarchy, and his authoritarian rule became increasingly unpopular. Parliament executed Charles I in 1649, but in the absence of any good alternative to succeed Cromwell, the Stuart heir to the throne, Charles II, was invited back.

The restoration of the monarchy was welcomed by a joyous population who hoped that Civil War was put behind them and looked forward to the reopening of the theater and the return of horse racing. Parliament and crown were reunited, but the exact nature of their relationship was not explicitly defined. Charles took advantage of this ambiguous space to expand royal power whenever he could.

Charles faced a complicated and precarious political environment, both at home and abroad. He had to manage the thankless task of trying to reconcile his loyal royalist supporters with suspicious and hostile Parliamentarians who had supported Cromwell. He also had to deal with a European landscape that included an economic rivalry with the Dutch and the ambitions of the French king, Louis XIV, for European dominance.

Clashes between English and Dutch commercial interests fueled popular support for the First and Second Anglo-Dutch Wars in the 1650s and the 1660s, but Parliament recoiled from providing the resources the king might use to support a standing army. Parliament wished to keep tight control of the purse strings, and memories of the way Charles I had turned a standing army against Parliament were still strong.

Short on funds, Charles II looked about for ways to augment his income and his power without going through Parliament.

He had reason to be grateful to Louis XIV, who had sheltered him and his family during their exile from England after the execution of his father. In addition, his beloved sister, Henrietta, was married to Louis’s brother. Charles also understood that Louis’s program of expanding French power in Europe required defeating the Dutch — which gave him an opening.

In 1662, in need of an infusion of cash, Charles sold the English interest in Dunkirk to Louis. This transaction, although unpopular, formed a precedent for a bigger deal. In 1670, Henrietta acted as an intermediary in the negotiations for the Treaty of Dover between England and France to ally the two nations against the Dutch. With this agreement, England formed a new Anglo-French alliance that led directly to the Third Anglo-Dutch War, which lasted from 1672 to 1674.

But there was more to the deal than just a military alliance. Secret provisions gave an annual stipend to Charles to help close a budgetary gap and enable him to evade parliamentary oversight. In return, Charles promised that he would break the English alliance with Sweden and the Dutch, formed as part of the settlement of the Second Anglo-Dutch War, and also publicly convert to Catholicism sometime in the future. (Charles was too canny to specify exactly when, and his actual conversion had to await his deathbed.)

Charles’s deal with Louis gave support to French ambitions for European domination, and in return Charles received resources to enable him to thwart the power of Parliament over the crown and return England to Catholicism.

Knowing that this deal would be unpopular — after all, it benefited Charles, not the English public — in a 17th-century version of “no collusion,” Charles denied the existence of the secret clauses of the Treaty of Dover. But such a deal could not remain secret for long, and by the 1680s rumors about these provisions percolated through the English elite who had been excluded from the negotiations. These suspicions helped to fuel a revived parliamentary resistance to Charles and stained his reputation for decades. During a time when the principle of parliamentary supremacy was still in flux, Charles sold out his own country to the French, a breathtaking example of corruption by a head of state at the behest of a foreign actor.

A century later, the story of Charles II’s treachery was on the minds of those crafting a new constitution for the United States.

During those deliberations, Gouveneur Morris and Charles Pinckney pointed to Charles as an example of a corrupt head of state, using his perfidy to argue for the emoluments and the impeachment clauses, as well as the participation of the Senate in ratifying treaties. During the debates on ratifying the constitution in the South Carolina legislature, Charles Cotesworth Pinckney cited Charles’s sale of Dunkirk to Louis as a reason to make presidential treaty-making subject to senatorial advice and consent. And Alexander Hamilton in the Federalist Papers underlined how Charles had fielded a standing army without respect to Parliament in the waning years of his reign.

That a scheming, feckless leader might sell out his own country was a very real threat in the minds of those tasked to create a constitutional framework for a new government. Perhaps few Americans remember Charles II, and certainly fewer still remember the Treaty of Dover. But our Constitution’s safeguards against the danger of foreign corruption still exist, derived in part from the 18th-century memories of Charles’s duplicity. It remains to be seen whether we have the political courage to use them or whether they will protect us.