President Trump announced he’s signing a proclamation on Friday declaring a national emergency to free up billions of dollars to build his wall on the U.S.-Mexico border. The move is the latest in a two-month showdown that included a 35-day partial government shutdown. Congress only voted to allocate $1.375 billion for border barriers – far short of the $5.7 billion Trump wanted.

It may seem like a drastic action, but he is hardly the first American president to take extraordinary steps for what he sees as the interest of the nation.

In fact, not only are national emergencies more common than most Americans probably realize, the nation is already subject to dozens of emergency declarations that are ongoing today.

From Abraham Lincoln’s decision to suspend habeas corpus in 1861 to Harry Truman’s ordering the Secretary of Commerce to seize control of the steel mills amid a 1952 wartime strike, presidents have occasionally seen fit to step outside the bounds of normal government. By proclaiming a national emergency, the President “may seize property, organize and control the means of production, seize commodities, assign military forces abroad, institute martial law, seize and control all transportation and communication, regulate the operation of private enterprise, restrict travel, and, in a variety of ways, control the lives of United States citizens,” according to a 2007 Congressional Research Service report.

But while scholars agree that the power to declare a national emergency is in fact implied within the executive powers given to the President by the Constitution, there’s at least one big difference between Trump’s situation and that of Lincoln or Truman.

Trump acts in an era in which presidents are required by law to take some additional steps when declaring a national emergency, thanks to the National Emergencies Act of 1976, signed by President Gerald Ford. In theory, it requires the President to spell out the powers from specific laws that make it legal for him to declare a national state of emergency, and requires the House and the Senate to review such a declaration every six months to see if it’s still necessary. To end a national emergency, both chambers of Congress could pass a joint resolution.

“The original idea for the law was to formalize the process because, in the past, presidents had simply proclaimed national emergencies and they went on indefinitely,” says Chris Edelson, author of Emergency Presidential Power: From the Drafting of the Constitution to the War on Terror, and professor of Political Science at American University.

Edelson characterizes this law as one of several passed after the Nixon presidency, fresh off Watergate and the Vietnam War, when Congress — all too aware of how a presidency could take a turn for the worse — took deliberate steps to safeguard against a president acting unilaterally. That was the same period that gave the United States the Ethics in Government Act and the Foreign Intelligence Surveillance Act, for example.

In reality, however, the law has proved little-used. A 2014 USA Today investigation reported that Congress has renewed them without doing the required periodic check-ins. Thirty-one of the national emergencies declared via the National Emergencies Act since 1976 are technically still in effect, having never been formally ended, according to CNN. Just as presidents have declared war without Congressional approval, even after the War Powers Resolution was passed in that same mid-1970s era, presidents have exercised their right to declare an emergency without much practical worry about being checked.

In terms of why this power hasn’t been reigned in more, partisanship could be at play. Edelson suggests it’s possible that, while members of Congress know they can curtail the President’s power to declare a national emergency, they may not be inclined to do so if the President is also the head of their party. The matter is also an example of how different people in government may have different interpretations of the extent of presidential powers. Some lawmakers may, despite the 1976 act, feel that the president must retain this particular power for the sake of national safety.

“The Constitution doesn’t grant emergency powers to the President, but some people think that power is implied,” says Edelson, “and some members think presidents should have this power.”

Ongoing U.S. National Emergencies

Though the word emergency might imply a temporary situation, a look at the list of times the president has used that power makes it immediately clear that a national emergency is something different.

Here’s a list of national emergencies that were declared after the passage of the National Emergencies Act that are still technically in effect as of Jan. 8, 2019, as listed in the Federal Register.

1. The National Emergency With Respect to Iran, declared Nov. 14, 1979, in the early days of the Iran hostage crisis, has been going on for more than 39 years.

2. The National Emergency With Respect to the Proliferation of Weapons of Mass Destruction was declared Nov. 14, 1994, in order to consolidate two earlier national emergencies having to do with weapons of mass destruction, at a time at which many world powers were debating how to handle the issue of chemical weapons. It has been going on for more than 24 years.

3. The National Emergency With Respect to Prohibiting Transactions with Terrorists Who Threaten to Disrupt the Middle East Peace Process was declared on Jan. 23, 1995, following a deadly suicide bombing in Jerusalem and an administration review that concluded more could be done to limit terrorists’ access to money. It has continued for nearly 24 years.

4. The National Emergency With Respect to Prohibiting Certain Transactions with Respect to the Development of Iranian Petroleum Resources was declared March 15, 1995 — 23 years and 9 months ago. It was designed to prevent a deal between U.S. oil company Conoco and Iran.

5. The National Emergency With Respect to Blocking Assets and Prohibiting Transactions with Significant Narcotics Traffickers Centered in Colombia was declared Oct. 21, 1995, about 23 years ago. That month, it had been reported that the Cali Drug Cartel, specifically, was using American companies to launder cash.

6. The National Emergency With Respect to Regulations of the Anchorage and Movement of Vessels with Respect to Cuba was declared March 1, 1996, nearly 23 years ago. The month prior, two civilian planes were shot down near Cuba by fighter jets.

7. The National Emergency With Respect to Blocking Sudanese Government Property and Prohibiting Transactions with Sudan was declared Nov. 3, 1997 — 21 years ago — and instituted comprehensive economic and trade sanctions prohibiting most trade and all U.S. investments because of the terrorists allowed to live there.

8. The National Emergency With Respect to Blocking Property of Persons Who Threaten International Stabilization Efforts in the Western Balkans was declared more than 17 years ago, on June 26, 2001, to impose sanctions on those helping armed Albanian insurgents in Macedonia.

9. The National Emergency With Respect to Export Control Regulations was declared more than 17 years ago, on Aug. 17, 2001, to re-up presidential power to control exports in a national emergency since the Export Administration Act of 1979 lapsed.

10 and 11. The National Emergency by Reason of Certain Terrorist Attacks and the National Emergency With Respect to Persons who Commit, Threaten to Commit, or Support Terrorism were both declared in September of 2001, 17 years ago, after the deadly terrorist attacks of 9/11.

12. The National Emergency With Respect to Blocking Property of Persons Undermining Democratic Processes or Institutions in Zimbabwe was declared nearly 16 years ago on March 6, 2003, to punish people associated with the despotic reign of Robert Mugabe.

13. The National Emergency With Respect to Protecting the Development Fund for Iraq and Certain Other Property in Which Iraq has an Interest was declared 15 years and seven months ago on May 22, 2003, following the U.S. invasion of Iraq.

14. The National Emergency With Respect to Blocking Property of Certain Persons and Prohibiting the Export of Certain Goods to Syria was declared on May 11, 2004, more than 14 years ago, when the Bush administration said Syria was supporting terrorism and interfering with U.S. efforts in Iraq.

15. The National Emergency With Respect to Blocking Property of Certain Persons Undermining Democratic Processes or Institutions in Belarus was declared June 16, 2006, more than 12 years ago, in reaction to charges of fraud in Belarus’ presidential election and inhumane treatment of those protesting the results.

16. The National Emergency With Respect to Blocking Property of Certain Persons Contributing to the Conflict in the Democratic Republic of the Congo was declared Oct. 27, 2006 — 12 years ago — after riots and violence over the Congolese presidential election runoff.

17. The National Emergency With Respect to Blocking Property of Persons Undermining the Sovereignty of Lebanon or Its Democratic Processes and Institutions was declared Aug. 1, 2007, more than 11 years ago, as Lebanon battled a siege by Islamic militants.

18. The National Emergency With Respect to Continuing Certain Restrictions with Respect to North Korea and North Korean Nationals was declared on June 26, 2008 and has continued for more than 10 years. It maintains that there’s evidence the dictatorship’s nuclear program is still a threat, but was part of a deal that would remove it from the U.S. terrorism blacklist if Pyongyang moved towards denuclearization.

19. The National Emergency With Respect to Blocking Property of Certain Persons Contributing to the Conflict in Somalia was declared on April 12, 2010, and has continued for more than eight years. It was a response to threats posed by Somali pirates that had ramped up within the previous year.

20. The National Emergency With Respect to Blocking Property and Prohibiting Certain Transactions Related to Libya was declared on Feb. 25, 2011 — nearly eight years ago — and froze assets of Libya’s then-leader Colonel Muammar Gaddafi.

21. The National Emergency With Respect to Blocking Property of Transnational Criminal Organizations was declared on July 25, 2011, more than seven years ago, amid reports that such crime was on the rise. It specifically targeted four groups: Los Zetas (Mexico), The Brothers’ Circle (former Soviet Union countries), the Yakuza (Japan), and the Camorra (Italy).

22. The National Emergency With Respect to Blocking Property of Persons Threatening the Peace, Security, or Stability of Yemen was declared on May 16, 2012, more than six years ago. At the time, the U.S. was involved in a political transition following the presidential election ending Ali Abdullah Saleh‘s rule after more than three decades.

23. The National Emergency With Respect to Blocking Property of Certain Persons Contributing to the Situation in Ukraine was declared on March 6, 2014. The four-plus-year-old order was part of retaliatory sanctions imposed on Russia for occupying Crimea.

24. The National Emergency With Respect to Blocking Property of Certain Persons With Respect to South Sudan was declared on April 3, 2014 — four years and nine months ago — amid the ongoing civil war there.

25. The National Emergency With Respect to Blocking Property of Certain Persons Contributing to the Conflict in the Central African Republic was declared on May 12, 2014, more than four years ago, in light of rising violence towards humanitarian aid workers and the growing number of refugees fleeing to neighboring countries.

26. The National Emergency With Respect to Blocking Property and Suspending Entry of Certain Persons Contributing to the Situation in Venezuela was declared on March 8, 2015, just under four years ago. The White House tried to block Venezuelans violating human rights of fellow citizens, as President Nicholas Maduro jailed opposition leaders and the country’s economy was in a downward spiral. In 2018, this order was expanded.

27. The National Emergency With Respect to Blocking the Property of Certain Persons Engaging in Significant Malicious Cyber-Enabled Activities was declared on April 1, 2015 — three years and nine months ago — following reports of Chinese cyberattacks on U.S. coding website Github, and hacks at stores like Home Depot and Target.

28. The National Emergency With Respect to Blocking Property of Certain Persons Contributing to the Situation in Burundi was declared on Nov. 23, 2015, about three years ago, after a failed coup d’état created a climate of persecution there.

29. The National Emergency With Respect to Blocking the Property of Persons Involved in Serious Human Rights Abuse or Corruption was declared on Dec. 20, 2017, about a year ago. Dozens worldwide were hit by sanctions, notably Myanmar general Maung Maung Soe for his role in atrocities against Rohingya Muslims.

30. The National Emergency With Respect to Imposing Certain Sanctions in the Event of Foreign Interference in a United States Election was declared on Sept. 12, 2018, about four months ago, in an attempt to safeguard the midterm elections amid the ongoing investigation into Russian interference in the 2016 presidential election.

31. The National Emergency With Respect to Blocking Property of Certain Persons Contributing to the Situation in Nicaragua was declared on Nov. 27, 2018, just over a month ago. The country has been embroiled in protests calling for the ouster of President Daniel Ortega.

Write to Olivia B. Waxman at olivia.waxman@time.com.