By the time Jefferson was elected president, he was an experienced lawmaker as well as a seasoned executive. As two-term governor during wartime, ambassador, secretary of state, and vice president, Jefferson was well aware that necessity sometimes required extraordinary acts of executive discretion. As representative of his state, participant in the formation of his state's constitution, reformer of his state's laws, discussant with Madison, and cofounder of his party, Jefferson also understood the sometimes strained relationship of executive prerogative and consent. Throughout his career, he attempted to preserve the law by interpreting it strictly while at the same time explaining that a strict construction of the law would require that the law be set aside during times of necessity or enterprise, on the condition that the executive submit to political judgment by announcing his extralegal activity. His transformation of the prerogative power turned on what he believed to be the connection between executive power and majority rule.

The Louisiana Purchase has been considered the greatest achievement of Jefferson's administration but also an example of political principle yielding to practical necessity. Henry Adams called the event “so momentous” that it “defied measurement” and speculated that the purchase “ranked in historical importance next to the Declaration of Independence and the adoption of the Constitution.” But, in Adams's view, the Purchase's importance derived as much from its constitutional legacy as from its size, for Jefferson's purchasing and incorporating Louisiana was the fatal blow to the strict construction of the Constitution.