In addition to his foreign policy duties, Van Buren quickly emerged as an important advisor to Jackson on major domestic issues like the tariff and internal improvements. The Secretary of State was instrumental in convincing Jackson to issue the Maysville Road veto, which both reaffirmed limited government principles and also helped prevent the construction of infrastructure projects that could potentially compete with New York's Erie Canal. He also became involved in a power struggle with Calhoun over appointments and other issues, including the Petticoat Affair. The Petticoat Affair arose because Peggy Eaton, wife of Secretary of War John H. Eaton, was ostracized by the other cabinet wives due to the circumstances of her marriage.