The Shifting Twenty-First-Century Presidency: Assessing the Implications for America and the World - Hardcoverby Tevi Troy (Editor) The role and range of the American presidency has undergone significant changes in the twenty first century, with George W. Bush, Barack Obama, Donald Trump, and now Joe Biden transforming the office in distinct ways. Many but not all of these changes stem from the numerous crises of this young century: 9 11 and the resulting war on terror, Hurricane Katrina, the Great Recession, the COVID 19 pandemic, and the social unrest of