[27][b] Shortly after the wedding, Joshua Johnson fled England to escape his creditors, and Adams did not receive the dowry that Johnson had promised him, much to the embarrassment of Louisa. Adams noted in his own diary that he had no regrets about his decision to marry Louisa.[29]
In 1796, Washington appointed Adams as the U.S. ambassador to Portugal.[30] Later that year, John Adams defeated Jefferson in the 1796 presidential election. When the elder Adams became president, he appointed his son as the U.S. ambassador to Prussia.[31] Though concerned that his appointment would be criticized as nepotistic, Adams accepted the position and traveled to the Prussian capital of Berlin with his wife and his younger brother, Thomas Boylston Adams. The State Department tasked Adams with developing commercial relations with Prussia and Sweden, but President Adams also asked his son to write to him frequently about affairs in Europe.[32] In 1799, Adams negotiated a new trade agreement between the United States and Prussia, though he could never complete an agreement with Sweden.