SAN DIEGO, CA -- As someone who often takes a conservative stance on issues, I once again find myself in the curious position of defending President Obama to disillusioned critics within his own liberal base. And once again, I'm glad to do it.
This time, it's Afghanistan. In one of the most complicated corners of the world, Obama -- and his military commanders -- are pursuing a troop build-up that has those on the anti-war left shaking their heads. Since taking office, Obama has sent an additional 21,000 troops to Afghanistan. And more could be on the way.
In a recently leaked report to the White House, Gen. Stanley A. McChrystal, the U.S. commander in Afghanistan, called the situation "serious" but insisted that "success is achievable."
McChrystal didn't specifically ask for more troops. But that request is expected soon. Senior Pentagon officials are expected to ask for as many as 45,000 additional American troops this month. Currently, there are about 68,000 U.S. troops in Afghanistan.
Some conservatives are also expressing reservations about a troop build-up. Most notably, columnist George Will suggested in the Washington Post this week that the Obama administration begin the process of "rapidly reversing the trajectory of our involvement in Afghanistan." No fan of nation-building, Will is concerned that the U.S. military strategy of "clear, hold and build" is unworkable.
But for Obama, the real worry is how all this is going over with the American people and with his liberal base. And, thus far, the answer -- on both counts -- is not very well. A CNN/Opinion Research Corp. poll this week showed that 57 percent of Americans are opposed to the war in Afghanistan, an increase of 11 percentage points since April.
Meanwhile, many liberals are especially squeamish about Afghanistan. They have no problem with nation-building. In the 1960s, the left was squarely behind the Peace Corps, which allowed young people to build the infrastructure of developing countries.
Liberals love to build things, especially with other people's tax dollars. They just don't like the idea of U.S. troops doing the building. Maintaining a military presence on foreign soil makes the left nervous because it feeds the perception that the United States has an itch for imperialism and can't go long without scratching it.
Besides, putting troops on the ground brings back memories of what liberal columnist Robert Scheer of the San Francisco Chronicle recently called America's "most disastrous overseas adventure": the Vietnam War.
Ever notice how, for those who came of age in the '60s and '70s, every inkblot on a map looks like Vietnam? And every president who commits troops to a foreign theater -- for whatever reason -- begins to morph into Lyndon Johnson?
Admittedly, Obama got himself into this predicament by seizing what had been the Democrats' mantra since the Sept. 11 attacks: that President Bush was fighting the "wrong war" in Iraq, as opposed to the "right war" in Afghanistan.
You know what that was about: more ghosts from Vietnam. Since the wimpy presidential campaign of 1972 Democratic nominee George McGovern, Democrats have fretted over being perceived by voters as weak on national defense.
In 2004, Democratic presidential nominee John Kerry decided that the way out of that predicament was to argue that Bush, while doing the right thing in combating terrorism, was distracted by Iraq when he should have been focused on Afghanistan.
Obama -- who was, in a sense, also running against Bush or at least the Bush legacy -- picked up the same line of attack. He has often called Afghanistan a "war of necessity" and has emphasized the need to defeat the Taliban and al Qaeda militants operating there and neighboring Pakistan. During the campaign, Obama also talked about how, if elected president, he would listen to the generals on the ground.
Now that he is president, Obama must feel as if he has no choice but to see things through in Afghanistan or risk being labeled a hypocrite and opportunist.
But holding the line in Afghanistan doesn't just make political sense for Obama. It's also common sense. Forget nation-building. Let's focus on the need to maintain an outpost in a dangerous neighborhood so we can ferret out our enemies and eliminate them before they can strike us again.
It's time to grow up and confront an unpleasant reality, folks. The world changed on September 11, 2001, and it's not a question of "if" another attack comes but "when." Retreat isn't an option. Nor is surrender. And nor is a kind of wistful isolationism where U.S. troops pack up their gear and come home, where bygones will be bygones and where al Qaeda won't follow. We can fight this battle on the streets of Kabul or in Kansas City.
That is the choice the president faces. Obama's critics can spend all the time they want wishing it were otherwise. But it isn't.
The opinions expressed in this commentary are solely those of Ruben Navarrette Jr.