President Donald Trump's <a href="https://www.thenational.ae/world/the-americas/trump-promises-to-crush-al-qaeda-and-isil-in-afghanistan-1.621762">Afghanistan policy speech</a> underscored the capitulation of his <a href="https://www.thenational.ae/world/asia/trump-s-afghanistan-strategy-receives-praise-from-pundits-military-observers-and-afghan-officials-alike-1.622044">nativist populism</a> to conventional Washington thinking. More importantly, it demonstrated how Afghanistan has quietly emerged as America's new Vietnam. Afghanistan isn’t Vietnam in that tens of thousands of Americans are dying in a lost cause, or that the country is being socially and politically ripped apart over controversy about its wisdom and morality. To the contrary, there is no meaningful national or even public policy debate about an <a href="https://www.thenational.ae/world/asia/us-in-afghanistan-mattis-confirms-trump-administration-has-decided-on-new-strategy-1.621268">Afghanistan strategy</a>, and even the most informed experts haven't been able to posit any serious alternative approaches. But it is a new Vietnam in the sense that the conflict is simultaneously unwinnable – because neither the government nor the public is willing to consider committing the resources necessary to secure anything resembling traditional definitions of "victory" – and yet, conventional wisdom holds, it <a href="https://www.thenational.ae/world/the-americas/trump-backtracks-on-afghan-troop-pullout-1.621712">cannot be abandoned</a> without intolerable domestic political costs. _________________ <strong>Read more:</strong> _________________ This is the dilemma that confronted Lyndon B Johnson and Richard Nixon. Both knew the war could not be won, yet neither was willing to embrace defeat. Nixon acted only once he was sure that he could secure a far greater strategic victory by forging an anti-Soviet entente cordiale with China in the wake of North Vietnam’s triumph. What Mr Trump <a href="https://www.thenational.ae/opinion/can-trump-s-revised-strategy-for-afghanistan-work-1.621967">is proposing</a> is a new iteration of the very same George W Bush and Barack Obama policies he thoroughly derided in the past. The United States will introduce a few more troops, but no one believes this can make a decisive difference with the <a href="https://www.thenational.ae/world/asia/taliban-dismiss-trump-s-afghan-strategy-as-nothing-new-1.621722">Taliban controlling more than half the country</a>. It may be enough to deny the Taliban an outright victory, but certainly not to defeat them. Washington will also intensify pressure on <a href="https://www.thenational.ae/opinion/trump-s-ultimatum-puts-pakistan-firmly-in-his-crosshairs-1.621969">Islamabad to try to coerce Pakistan</a> into cutting its ties to radical groups in Afghanistan. This is unlikely to work. Pakistan enjoys strong support from China, and the US depends on Pakistan for supply routes into Afghanistan and much more. Moreover, the Afghan war is, in part, a proxy conflict between Pakistan and India, and the Pakistanis lack any viable alternatives to these radical groups for securing their interests in Afghanistan. Therefore, the overwhelming likelihood is that <a href="https://www.thenational.ae/world/asia/trump-s-warning-to-pakistan-over-terrorism-meets-with-mixed-reaction-1.622021">Pakistan will largely ignore</a> American pressure and Washington will largely ignore Pakistan's noncooperation. There are three plausible defenses, each tenuous, of Mr Trump’s approach. First, it could be reasonably observed that he has inherited a fundamentally <a href="https://www.thenational.ae/opinion/donald-trump-s-path-forward-in-afghanistan-is-a-rebrand-not-a-step-ahead-1.621831">unmanageable situation</a> from his predecessors: the war is inherently unwinnable in any meaningful sense, while also being very difficult to disengage from politically. So, practically, he has little choice but to proceed with this slightly tweaked existing policy. _________________ <strong>More on Afghanistan:</strong> _________________ Second, it could be argued that such extreme ambiguity is useful in such a conflict. And in dealing with the Taliban some degree of ambiguity probably has strategic benefits. However, this runs directly counter to the <a href="https://www.thenational.ae/world/asia/trump-s-warning-to-pakistan-over-terrorism-meets-with-mixed-reaction-1.622021">strategy of pressuring Pakistan</a> with greater clarity and focus to disengage from the Taliban and, especially, the Haqani network. Even worse, it strongly contributes to the lack of clarity and honest public debate in the US about what the country is trying to achieve in Afghanistan and why: what in blood, treasure and energy this is worth; and what plausible alternatives, particularly involving disengagement, actually exist. Third, many would say that even though Mr Trump’s long-standing scepticism about the Afghan conflict was one of his most reasonable consistent opinions, it’s still preferable that he is deferring to his national security advisers and military leaders in this case. Does anybody really think that Mr Trump can, on his own, come up with a <a href="https://www.thenational.ae/world/nato-applauds-trump-s-afghanistan-strategy-1.622038">better strategy </a>for either "victory" or effectively managed disengagement than these professionals? He has yet to demonstrate wise leadership on far simpler challenges, so an approach based on presidential improvisation is, in this case, a terrible idea. _________________ <strong>More from Opinion on Afghanistan:</strong> _________________ But there is a striking irony at work. Mr Trump’s national security adviser, HR McMaster, is both a principal architect of the extension of retreading an Afghan policy designed to simply buy time and avoid defeat, and the author of one of the most insightful books about the failure of the military to speak truth to power during the Vietnam War. In <em>Dereliction of Duty</em>, Gen McMaster outlined how military leaders at the time knew that Johnson's politically driven strategy of systematically increasing military pressure on North Vietnam was doomed to failure. Yet, as he painstakingly details, they allowed Johnson's domestic political agenda to shape strategic decision-making in a way that made success impossible and primed a disaster. The stakes <a href="https://www.thenational.ae/world/asia/war-weary-afghans-watch-trump-strategy-with-mix-of-hope-and-scepticism-1.622019">are far lower</a> in Afghanistan now. Yet America is once again fighting an "unwinnable" and open-ended war with no plausible exit strategy. And the military leadership is once again deferring to domestic political considerations. As for Mr Trump's <a href="https://www.thenational.ae/world/the-americas/donald-trump-healer-or-divider-of-a-nation-1.622687">vainglorious rhetoric</a> about a US "victory" and <a href="https://www.thenational.ae/world/asia/taliban-dismiss-trump-s-afghan-strategy-as-nothing-new-1.621722">Taliban "defeat"</a> in Afghanistan, this can only be described as blatant lying to the American people, since neither his policies nor any plausible alternatives can achieve either. What is dangerously absent is an honest conversation about what’s at stake for Washington in Afghanistan, the price that’s worth paying, and how long the country is willing to sustain the longest war in its history. Follow The National's Opinion section on <strong><em><a href="https://twitter.com/NationalComment">Twitter</a> </em></strong>