Which was more consequential: the bombing of Hiroshima or the moon landing?
Looking back on history, it’s easy to decide. Hiroshima led to the end of World War II, the use of a powerful new weapon and the start of the Cold War, so it was clearly more important in the long run.
But things would look different if we were all living on a moon base right now. And they might look different in the future.
One year into the second Trump administration, it’s hard to tell which of the president’s many unprecedented actions will prove the most consequential. Will it be his revival of the long-dormant power to levy tariffs? His attempts to undermine the civil service? The aggressive expansion of immigration enforcement?
We don’t know yet. A lot depends on what he does next, what Congress and the Supreme Court do and how ordinary Americans respond.
Still, it’s helpful to think about the question, so we asked some prominent historians and political scientists to share their thoughts on Trump’s most consequential action of the past year.
Here’s what they said.
Hiring Stephen Miller
“I think we will ultimately learn that Miller was the one making the most alarming and consequential decisions during Trump’s first term and then giving the orders to implement them.”
— Heather Cox Richardson, history professor at Boston College and writer of “Letters from an American”
Expanding Immigration and Customs Enforcement
“In my opinion, the most consequential action of Trump’s first year is converting ICE into a force of masked marauders dedicated to terrorizing Americans and savaging their cities. What began as an ugly assault on any and all immigrants — legal and otherwise — has devolved into a bloody reign of terror aimed at cowing Americans into silence and submission, in a quest for absolute and unending power. Trump has openly, aggressively turned the United States government against its own people. In so doing, he has threatened the survival of American democracy, making him the single most malevolently destructive president in U.S. history — and perhaps also the president who has done the most to unite and rouse ‘We the People’ in defense of democracy as an outcome.”
— Joanne B. Freeman, professor of history and American studies at Yale University, host of the “History Matters” podcast and author of “The Field of Blood: Violence in Congress and the Road to Civil War”
Expanding ICE raids
“Trump’s ICE raids have the potential to turn against the president if the narrative shifts from going after ‘illegal immigrant criminals’ to targeting blue state Americans. In 1850, Congress passed the Fugitive Slave Act, requiring citizens in free states to cooperate in the capture and return of runaways. The act provoked a firestorm among Northerners who believed the federal government had infringed upon their rights. ICE overreach will likely be a key factor in at least the next two electoral cycles.”
— David S. Brown, professor of history at Elizabethtown College and author of “In the Arena: Theodore Roosevelt in War, Peace, and Revolution”
Firing prosecutors who investigated him
“Bright Line Watch experts rate Donald Trump’s firing of Department of Justice officials who investigated him as the most serious threat to democracy of the events we’ve observed in his first year in office. In total, 85% of the political science experts we surveyed rated this action as posing an ‘extraordinary’ or ‘serious’ threat to American democracy.”
— Brendan Nyhan, political science professor at Dartmouth College and co-director of Bright Line Watch, a nonpartisan watchdog on American democracy
“It’s difficult to identify a single action as the most consequential, but perhaps the most consequential feature of President Trump’s second term has been his expansive, often unconstitutional use of executive power and the lack of any restraint from his own administration or party on his worst impulses. It’s hard to think of a president who has had such a thin legislative agenda in their second term, while wielding executive authority with such abandon. Of course, writing this as an academic based in the U.K., it seems increasingly plausible that his most significant action may prove to be his pursuit of Greenland, which still has the potential to collapse the post-1945 global order and start a geopolitical and economic cataclysm!” — Patrick Andelic, historian of U.S. liberalism, Congress and the 20th century Democratic Party at Northumbria University “I think his repudiation of rights, liberties and the separation of powers outlined in the U.S. Constitution captures the essence of it.” — Ellen Fitzpatrick, professor emerita of history at the University of New Hampshire and author of “The Highest Glass Ceiling: Women’s Quest for the American Presidency” “The most consequential act of Trump’s first year back in office was his pardon of the convicted Jan. 6 coup participants. Those pardons set the stage for not only the lack of consequences for doing violence in the president’s name, but also the shredding of federal institutions and obliteration of any authority outside Trump himself. “The use of a legal power traditionally held by the president to do something deeply wrong and illegal in the larger sense (pardoning those who had abetted his own lawbreaking) revealed the weaknesses of our institutions and the way the second Trump administration would operate. Rewarding lackeys willing to destroy democracy in order to serve his grievances created a template for every day that followed. The results have been horrific: Hundreds of thousands of deaths have already happened due to USAID cuts overseas. The country is building massive concentration camp-style detention facilities. And federal law enforcement officers are kidnapping and shooting people in the streets today, American citizens among them.” — Andrea Pitzer, author of “One Long Night: A Global History of Concentration Camps” “Trump’s most consequential first-year action may be his deliberate disruption of the cultural sector: canceling and redirecting federal cultural grants, undermining the independence and integrity of institutions like the Smithsonian and National Park Service, and imposing an ideologically distorted approach to the nation’s 250th anniversary. At a moment when the United States could have used the once-in-a-generation opportunity of the semiquincentennial to invest in museums and foster thoughtful engagement with the nation’s history, Trump instead reduced or eliminated funding, reshaped agency priorities and politicized the work of cultural institutions. The effects of this interference continue to reverberate nationwide, creating challenges for the cultural sector that will long outlast his presidency. That these actions occurred during the lead-up to the semiquincentennial will forever leave me wondering what might have been.” — John Garrison Marks, vice president of research and engagement at the American Association for State and Local History and author of “Thy Will Be Done: George Washington’s Legacy of Slavery and the Fight for American Memory” This is a preview of MS NOW’s Project 47 Newsletter. As President Trump continues implementing his ambitious agenda, get expert analysis on the administration’s latest actions and how others are pushing back sent straight to your inbox every Tuesday. Sign up now.
Ryan Teague Beckwith is a newsletter editor for MS NOW. He has previously worked for such outlets as Time magazine and Bloomberg News. He teaches journalism at Georgetown University’s School of Continuing Studies and is the creator of Your First Byline. 
Expanding executive power
Pardoning Jan. 6 participants
Disrupting American culture
