In roughly two months, President Barack Obama is going to announce the beginning of the end of America's longest war. He could not have known, when he initially set this summer for the beginning of the withdrawal of American troops from Afghanistan, that the timing would work out so perfectly. With Osama Bin Laden now dead, it's going to be a lot easier to begin pulling out of Afghanistan. The only question left to ask is how fast this drawdown will be accomplished.

Afghanistan has been called "the graveyard of empires" due to the fact that nobody has ever been able to truly conquer it -- and mighty empires have exhausted themselves trying. The United States entered Afghanistan after 9/11 to get rid of the Taliban and the safe havens for Al Qaeda in the country. After the initial success, however, President George W. Bush soon became distracted with his misadventure in Iraq, and never devoted the military force Afghanistan required. If Osama Bin Laden had been killed in the mountains of Tora Bora, it is very likely all American troops would be out of the country by now, but this opportunity was missed. Throughout Bush's tenure, we never had more than 30,000-40,000 troops in Afghanistan. Obama tripled this number in two "surges" (the first of which the media barely noticed), and there are now approximately 100,000 troops in the country. When the second of these escalations was announced, Obama set a deadline of this summer to announce his withdrawal plans.

Now that Bin Laden is dead, Obama has a wider range of options to choose from, in terms of how fast he's going to get our troops home. Bin Laden's death meant (among other things) that Obama has the political leeway to withdraw troops much faster now. The American public is tired of this war (when they even notice we're still fighting it), and the politicians have slowly come to realize this fact. Both Democratic and Republican support for the war is fading in Congress, which (again) makes Obama's task that much easier.

Obama will likely lay out only the first phase of his withdrawal plans in a few months, though. He'll announce the number of troops that will be coming home over the course of six months (or possibly as long as a year), and then he'll reassess the situation. This is in keeping with the way he's run America's wars so far, so he'll likely continue the same pattern. No matter what he announces, his critics will say he's either going too slow or too fast, but his choices fall roughly into three categories of troop withdrawal numbers: small, medium, and large.

Small (5,000-10,000)

The Pentagon is going to be arguing (as it almost always does) for a very slow withdrawal. If we had not just taken out Bin Laden, Obama may have only been able to announce a token withdrawal of five to ten thousand troops, still leaving over ninety percent of the American force in Afghanistan.

Obama could still choose this route, as there are voices within his administration who have never been in favor of the idea of a timetable for withdrawal in the first place. No American president wants to "lose" a war on his watch, and this fear might lead to an overabundance of caution in choosing how fast to get the troops out.

But this can now be countered with the oversimplification: "We got Bin Laden, therefore we won." This doesn't make perfect sense, of course, but it might be acceptable to a large portion of the American public, who are weary of a war which has lasted longer than any other in American history.

Pulling out only 5,000-10,000 troops might have been acceptable before the death of Bin Laden, but my guess is that it just isn't going to be fast enough a withdrawal at this point in time.

Medium (10,000-25,000)

Which brings us to the next step -- withdrawing 10,000 to 25,000 troops over the remainder of 2011. This seems the likeliest option for Obama to choose, to me at least. The numbers are big enough that it cannot be called a "token" withdrawal, but not so large as to give the image of just abandoning the country to its fate. This would still leave roughly 75,000-90,000 troops in Afghanistan next year, which is still over twice the number Bush ever devoted to the war. Obama will likely (no matter how fast he withdraws initially) review the Afghanistan situation at the end of this year, and could then elect to slow the withdrawal after a fairly large initial pullout, if circumstances on the ground merit it. Obama could also speed up the withdrawal in 2012.

As I stated, Obama's going to open himself up to criticism no matter what plan he announces. Some will say he's pulling out too fast, and some will say he should bring all the troops home immediately. By choosing a moderate -- but still substantial -- number somewhere in the 10,000-25,000 range, Obama can make the case that he's begun a significant withdrawal of troops but also that he's not just bugging out entirely all at once.

Large (25,000-plus)

There are people in the Obama administration who are going to argue for a large withdrawal of troops this year, probably led by Vice President Biden. Biden has always maintained that this summer's withdrawal would not just be a token few thousand, but truly the beginning of the end of America's involvement in this war. Obama could, for instance, announce that the second of his "surges" will all be coming home this year -- roughly 30,000-35,000 troops.

The American people would likely support such a bold move, although the more hawkish politicians would howl. More important than disgruntled politicians, however, is the fact that the Pentagon might fight such a large drawdown in a very public way. "Obama's not listening to his generals on the ground" will be the charge thrown at him. So far, Obama has done a good job of working with the Pentagon brass on all sorts of issues, and so this hasn't really been a problem for him yet. But a messy public fight with the Pentagon (even if the public supports the idea) could develop if the withdrawal plans are painted as too rash and too fast.

The American public is ready for the Afghanistan war to be over. We're approaching the tenth anniversary of the fighting there. We just hit the grim milestone this weekend of over 6,000 American soldiers who have died in the line of duty in Iraq and Afghanistan combined. Not many people even noticed this milestone, but the ten-year anniversary is going to get much more attention. When we get there, though, Obama will already have announced his withdrawal timetable. And by the end of the year, all of our troops are scheduled to be out of Iraq, as well.

Four years ago, America was pretty war-weary already. Barack Obama campaigned not (as some painted him) as an "anti-war" candidate, but rather as just an "anti-Iraq-war" candidate. He told America that he was going to pay more attention to Afghanistan and Pakistan, and begin withdrawing soldiers from Iraq. This is precisely what he has done. Obama was even asked, during the campaign, whether he would authorize a mission into Pakistan if we found Bin Laden hiding there. Obama said, in essence, "Absolutely!" He was denounced for saying this by both Hillary Clinton and John McCain -- McCain's answer was that Pakistan was a sovereign country, and so he would never unilaterally authorize a mission to kill Bin Laden there.

President Obama has now done exactly what he said he'd do, with spectacular success. This widens his options and increases public support for announcing a major drawdown of troops from Afghanistan. "We got Bin Laden, now let's go home" is going to become the refrain of many. Oversimplification though this may be, it's likely going to be enough for most Americans.

Instead of a gigantic political battle over the question of whether to withdraw troops (remember the extended political fracas over getting out of Iraq?), the entire political discussion in the next few months over Afghanistan is going to be how many troops we can withdraw, and how fast we can bring them home. No matter what Obama decides as his target number for the first phase of this withdrawal, it's going to be a lot easier for him to sell his plan now that Bin Laden is no more.

-- Chris Weigant

Cross-posted at Business Insider
Cross-posted at The Huffington Post

Follow Chris on Twitter: @ChrisWeigant