While the relationship between the legislative, executive, and judicial branches has remained largely the same, public perceptions of the president's place in the system have changed (Jeffrey Tulis, 1990). In the twentieth century, a strong executive emerged and was institutionalized in American national politics. Although the authors predicted that Congress would be the predominant branch of government, contemporary presidents have formidable formal and informal governance resources. As a result, public expectations of presidents have grown and created a gap between expectations and formal powers. In an attempt to explain presidential power and its limits, four major, often conflicting, theories of presidential power have emerged over the past four decades. For Neustadt, “presidential power is the power to persuade” (Nuestadt, 11). Persuasion and bargaining are the means that presidents use to influence policy. Presidents must “bargain” to influence both Congress and the executive branch. Neustadt argues that presidents cannot lead directly. In other words, just because a president says he wants something done doesn't mean it will be done. Instead, presidential power is a function of his ability to persuade relevant Washington actors (staff, members of Congress, bureaucrats) that it is in their interest to cooperate. In short, powerful or successful presidents are those who know how to bargain effectively with relevant actors. Franklin Delano Roosevelt (FDR) is the best example of success. Howell's theory of unilateral action describes a more isolated president. But this does not mean that his insistence on unilateral presidential action is invalid or does not provide us with a valid model for analyzing presidential power. Howell is certainly right to point out that control of Congress is made more difficult by the multiplication of unilateral tools that the President can use to change policies. The criticism arises from the fact that the title of his book seems to give the impression that his theory presents itself as an irreconcilable alternative to Neustadt's version of the presidential power of “persuasiveness”. Alternatively, Neustadt's theory suffers from institutional level analysis. Skrownek (1991) in his book “The Politics Presidents Make: Leadership from John Adams to Bill Clinton” suggested that there are clear patterns of contextual circumstances that can explain variation in presidential leadership. While not denying the role of personal attributes, he clearly demonstrated that presidents' personal contributions cannot be truly understood without an appreciation of the institutional contexts in which they operate (Skrownek