Just before he took office in January 2009, Barack Obama expressed an unwillingness to dig deeply into torture and other post-9/11 abuses carried out under the George W. Bush administration. “We need to look forward as opposed to looking backwards,” he explained. Twenty years after 9/11, the anniversary occasioned a great deal of looking back — not just remembrance but also critical reflection on how early U.S. errors in responding to the attacks helped drag the country into the political abyss it’s now struggling to escape. What the Bush administration called the Global War on Terror and the Obama administration renamed, bloodlessly, Overseas Contingency Operations always faced domestic political criticism from civil libertarians and the left. But the experience of the Trump presidency, and the necessity of understanding 9/11 in light of Donald Trump’s lawlessness, has transformed this view into an increasingly widespread consensus about America’s mistakes.

Subtle Tools,” by Karen J. Greenberg, is a useful entry in this analytical project. Greenberg, the director of the Center on National Security at Fordham Law School and a longtime critic of expanded state power after 9/11, draws a straight line between the early U.S. response to the attacks and the abuses of the Trump administration. “The legacy of the war on terror,” she writes, “has spawned a full-throated embrace of a new national vision” — one that, in her view, degrades both checks on executive power and liberal democracy itself. She quotes Trump, then a real estate developer, pondering two days after 9/11 that the devastated New York City skyline would make possible the creation of “a whole different city and world.” (Trump also, infamously, commented that the collapse of the twin towers meant that his own building was now the tallest in Lower Manhattan.)

Greenberg’s story centers on what she calls “subtle tools” — the malignant techniques of governance that became increasingly central after 9/11, and whose danger lies in how they “bestowed . . . powers without immediately calling attention to themselves.” Among these she identifies secrecy, disregard for norms, and imprecise and misleading language. Last on her list is “bureaucratic porousness,” a calculated confusion about who in government is responsible for what, which allows officials to expand their authority without being held accountable. This focus on the processes by which power is exercised, rather than the substance of what that power is used to achieve, sets Greenberg’s book apart from other studies of post-9/11 politics and the Trump presidency. “The true course of American politics and history,” Greenberg writes, “is apparent in how events happen as much as in what happened.”

Identifying these tools at work in the earliest days after 9/11, Greenberg tracks them through the next 20 years to the end of the Trump administration. She views the 2001 Authorization for Use of Military Force — passed by Congress to bless military action in response to 9/11, and used by every president since as legal justification for a steadily expanding list of counterterrorism operations around the globe — as the “Ur document in the war on terror and its legacy.” Where Bush interpreted the authorization broadly, the Obama administration sought to put in place procedural rigor but continued the expansive use of force overseas. Trump, when he arrived, stretched the statute even further. Today, though President Biden has withdrawn U.S. troops from Afghanistan, he’s given no indication that his administration will cease to deploy violence abroad under the 2001 authorization.

When it comes to the home front, Greenberg’s argument is most convincing, and troubling, when she turns to the operations of the Department of Homeland Security — an agency cobbled together after 9/11 with little coherent institutional purpose or oversight. Trump was able to use that weakness and disorganization to transform the department first into a machine for carrying out policies designed to brutalize immigrants, and then into a police force attacking people protesting the murder of George Floyd.

In describing Trump as the heir to a quietly nefarious model of governance, Greenberg sometimes implies a degree of forethought that’s at odds with the 45th president’s overt malice and carelessness. She points to Trump’s efforts to first undercut and then overturn the 2020 election, identifying his falsehoods about fake mail-in ballots as an example of “weaponizing the subtle tool of imprecise language.” But Trump’s rhetoric was not so much imprecise as it was an outright lie. Nor were his techniques particularly subtle. Trump’s conduct was so outrageous that, when situating him in historical context, it becomes difficult to identify where he represents an exaggeration of past trends and where he really is sui generis — but these distinctions matter, both for understanding how Trump fits into the post-9/11 landscape and for conceptualizing what will be required to fix what’s broken.

“Subtle Tools” necessarily ends not just with the arrival of the Biden administration in Washington but with the attempted insurrection at the Capitol on Jan. 6, which Greenberg reads as a culmination of political decay after 9/11. She worries about the vagueness of the term “domestic terrorist” as applied to the rioters, concerned that “the subtle tools would persist even in a newly defined context” in the form of an ill-conceived crackdown mirroring the response to 9/11. Yet she also hopes that the experience of the riot can help reestablish appreciation for the norms that have eroded over the past 20 years. Eight months after Jan. 6, this assessment seems too pessimistic and too optimistic at once: The long list of rioters pleading to relatively minor misdemeanor charges doesn’t yet foreshadow a power grab by security agencies, while the Republican Party’s continued willingness to embrace claims of election fraud shows that legal and political norms remain tattered. If the U.S. response to 9/11 changed everything, Jan. 6 — despite its horror — looks to have changed very little.

Subtle Tools

The Dismantling of American Democracy From the War on Terror to Donald Trump

By Karen J. Greenberg

Princeton.
270 pp. $29.95