(Washington Examiner): Many will welcome the United States-Taliban peace deal signed last weekend in Qatar. They see a war that has lasted nearly 19 years, taken the lives of nearly 3,600, wounded tens of thousands more, and cost trillions of dollars. They see a Taliban force that remains strong, with significant territorial control and financial strength. They see, in short, a war that has lasted too long and doesn’t seem winnable. The desire to get out of such a seemingly never-ending conflict is understandable, but we urge caution to our fellow citizens and President Trump. For all the failings and frustrations in Afghanistan since October 2001, the U.S. mission there has achieved some good things. This peace deal shouldn’t become an excuse to abandon Afghanistan, which would be a terrible moral and strategic error. This isn’t about nation-building but rather a matter of national security. The Trump administration must hold firm to a conditions-based approach to this deal. If the Taliban lives up to its word, the U.S. should do the same. If the Taliban breaks its word, which is increasingly likely in the second half of the deal’s implementation, Trump or his successor must be ready to return some U.S. forces to Afghanistan and exert renewed military pressure on Taliban forces. As structured, the deal holds the U.S. to a sharp timeline for troop drawdowns. The U.S. is pledged to reduce its force level to 8,600 over the coming 135 days. But, if the Taliban conform with its own obligations to suspend attacks and obstruct external terrorist groups such as al Qaeda, the U.S. will follow through, withdrawing all its forces over the next nine and a half months. This adds up to a 14-month timeline for total withdrawal of all U.S. forces from Afghanistan. Such a rapid timeline will encourage our NATO partners to expedite their own drawdowns. It will complicate U.S. commander Gen. Scott Miller’s contingency planning and freedom of action. It is possible that the Taliban and its Haqqani network allies will abide by their obligations in the second half of this agreement. Perhaps they will pursue serious negotiations with the Afghan government, joining the political process with influence instead of trying to tear it down with bombs. But there’s reason to fear an alternative outcome. Namely, that the Taliban will wait toward the latter end of the 14-month withdrawal window and then launch a campaign of limited but steadily escalating violence against the Afghan government. The Taliban is a keen strategist and will want to maximize its leverage for the moment the last U.S. soldier leaves Afghanistan. That will become a critical issue if the Trump administration or its successor refuses to alter the withdrawal timetable, even if the Taliban breaks its word. With U.S. popular opinion increasingly opposed to our continuing presence, there’s a risk that political expediency will take precedence over what is best for national security. And there are two risks in that premature, nonconditions-based approach. First, it would allow the Taliban to realign with its ideological partners, al Qaeda. While the Taliban fight against the Islamic State, the group’s affinity with Osama bin Laden’s group is long-standing. If the Taliban is able to provide al Qaeda or other transnational jihadists a safe haven, it will do so. Then, we will be back where we were in the months preceding Sept. 11, with threats metastasizing in the absence of our influence. Entertaining that threat would be an intolerably idiotic dereliction of duty. A premature withdrawal would also jeopardize the Afghan government. While the U.S. should not be operating under some delusion that Afghanistan will become a Western-style democracy, it would be a moral stain for the U.S. to give the Taliban space to defeat the government. In part, that’s because Afghanistan’s multisectarian society has a manifest majority opinion in opposition to Taliban dominance. But, there’s a simpler reason we should want to avoid Kabul’s fall: the striking dichotomy of prospective risk and reward. The risk of that outcome is that the Afghan people and democratic government would be subsumed by a fanatically anti-American regime, a regime that would find institutions of power via which to fuel its jihadist impulses. Alternatively, the prospective reward is that the U.S. retains an ally that will help stabilize a fractious region and that is supportive of our long-term counterterrorism interests. We note with some concern that the U.S.-Taliban agreement makes prisoner release commitments with which the Afghan government is presently uncomfortable. Trump must learn from President Barack Obama’s mistake. Although popular with voters, Obama’s withdrawal from Iraq led directly to an Iranian sectarian agenda ruling in Baghdad on the one hand and ISIS’s bloody caliphate on the other. Numerous terrorist attacks followed from Paris to Orlando, and U.S. forces were pushed back to the battlefield.