Editor’s Note: This is the most recent post in a mini-symposium leading up to tomorrow’s en banc oral argument in the US Court of Appeals for the District of Columbia Circuit in Al Bahlul v. United States. You can check out all of the pieces in the series here.

Tomorrow, the US Court of Appeals for the District of Columbia will hear oral argument in Al Bahlul v. United States for the fourth time overall, and the second time en banc. At issue in Al Bahlul IV is the scope of congressional authority to “define and punish” offenses for prosecution under the military commission system if the particular offense — conspiracy — is not recognized as a war crime under international law. An expansive view of congressional power in this area would raise important separation of powers issues and could threaten to usurp Article III judicial authority. The numerous blog posts, law review articles, and amicus briefs written in relation to this case attest that there is much to be said regarding the legal merits of this important constitutional question.

But just as important is the pragmatic question of whether expanding the jurisdiction of military commissions beyond law of war violations is indeed necessary to reduce impunity or to address “logistical and security gaps” in federal court prosecutions, as was argued by Peter Margulies last week. The available evidence suggests that our federal courts are capable of handling complex international terrorism cases, including prosecution of dangerous individuals and suspects who are apprehended abroad.

When similar questions arose a few years ago, Human Rights First, where one of this post’s authors is International Legal Counsel, partnered with veteran prosecutors, including the other author of this post, to assess the capability of federal courts to handle criminal cases arising from international terrorism. The result was In Pursuit of Justice: Prosecuting Terrorism Cases in the Federal Courts, a 140-plus page report that analyzes in detail the capacity of the federal criminal justice system to try individuals accused of international terrorism.

The report was not abstract or academic. It was based on a large data set of actual terrorism prosecutions, including cases brought both before and after 9/11, and addressed a host of practical issues confronting prosecutors, the courts, and law enforcement officials that arise in real-world terrorism prosecutions. Among other issues, the report addressed the challenges of preserving the secrecy of information that could compromise national security, ensuring the admissibility of evidence and availability of witnesses for crimes committed in other parts of the world, and how to ensure the safety of judges, jurors, witnesses, and other trial participants. As the report notes, serious challenges arise, but these challenges are not unique to international terrorism cases and our federal courts have proven capable of adapting to address them. Indeed, the overwhelming evidence gathered and analyzed in the report suggests that federal courts are capable of handling the logistical and security issues that arise in international terrorism prosecutions.

Developments since the publication of In Pursuit of Justice further support the report’s findings. The most recent data released by the Justice Department shows nearly 500 convictions related to international terrorism were obtained between September 11, 2001, and December 31, 2011 (not including convictions that remain under seal, proceedings that were still ongoing, or convictions stemming from purely domestic terrorism charges). Attorney General Lynch also noted just last week that since 2013 alone, DOJ has charged more than 70 individuals in relation to homegrown extremism and attempts to become foreign fighters. Moreover, contra the suggestion that capturing suspects abroad and bringing them before our federal courts is too arduous, complex, cost-prohibitive, or limited to the embassy bombings cases, since 9/11 we have captured and convicted more than 67 individuals from dozens of countries around the world in a range of circumstances and in connection with diverse terrorist plots.

As our report noted, military courts have a role to play in the prosecution of individuals who are subject to trial under the laws of war. The report explicitly disclaims any suggestion that it would be wise or feasible for the civilian justice system to supplant the military justice system during times of armed conflict. What the facts demonstrate, however, is that there is no practical need to expand the reach of military commissions beyond prosecution of recognized war crimes because of some perceived failing of our federal courts.

Thus, before considering whether to expand the reach of military commissions to encompass prosecution of offenses not recognized as war crimes, it is worth taking a step back to consider not just whether such a step is constitutional, but also what practical considerations support doing so. As Judge Tatel argues in his concurring opinion in Al Bahlul III, declining to expand the jurisdiction of military commissions beyond prosecuting violations of the law of war does not prevent the government from ensuring that those who conspire to commit terrorism are appropriately punished. As Tatel notes and our report demonstrates, “the government can always fall back on the apparatus it has used to try federal crimes for more than two centuries: the federal courts.”