For nearly a decade, drone strikes have been central to America's counterterrorism policy. Operated from remote locations, the small aircraft can hover over targets for long periods of time and kill extremists with precision without risking American casualties. President Barack Obama found drones so effective and useful that over two terms, he approved 542 strikes that killed 3,797 people in non-battlefield areas where American forces were not directly engaged, including Pakistan, Yemen and Somalia. But this seductive tool of modern warfare has a dark side. Seemingly bloodless and distant, drone strikes can tempt presidents and military commanders to inflict grave damage without sufficient forethought, violating sovereign rights and killing innocent civilians. Civilian deaths during Mr. Obama's tenure undermined American counterterrorism operations and became a recruiting tool for more extremists.
Mr. Obama was persuaded to impose sensible constraints on the use of drone strikes between 2013 and 2016. In traditional war zones, military commanders make these decisions without interagency review, and the threshold for acceptable civilian casualties is less strict. Now comes disturbing news: President Trump and his administration are moving to dilute or circumvent the Obama rules. This could have disastrous outcomes, not least because Mr. Trump seems even more enticed by drone warfare than Mr. Obama was. In the days since his inauguration, the tempo of airstrikes has increased significantly. Mr. Trump has already granted a Pentagon request to declare parts of three provinces in Yemen, where Saudi Arabia is fighting Iranian-backed Houthis rebels, to be an "area of active hostilities." This, The Times has reported, would enable more permissive battlefield rules to apply.
The president is also expected to soon approve a Pentagon proposal to do the same for parts of Somalia, where militants of the Shabab who are linked to Al Qaeda threaten regional stability. Military commanders often chafe at civilian oversight. But there is no evidence that the Obama rules have slowed counterterrorism efforts, and there are good reasons to keep them in place, including the fact that the legal basis for such strikes lacks credibility because Congress never updated the 2001 authorization for war in Afghanistan to take account of America's expanded military action against terrorists in Syria, Yemen and Libya.
Mr. Trump should heed the advice of national security experts who have urged the retention of strict standards for using force in non-battlefield areas and warned how even a small number of civilian deaths or injuries can "cause significant strategic setbacks" to American interests. He has already seen how a badly executed mission can have disastrous results: the raid in Yemen in January that resulted in the deaths of a member of the Navy's SEAL Team 6 and numerous civilians, including children. And as most experts agree, killing terrorists does not by itself solve the threat from extremists. For that, Mr. Trump will need a comprehensive policy that also deals with improved governance in the countries where terrorists thrive and with ways to counter their violent messages on social media.