The strategic and humanitarian costs of the conflict in Syria continue to rise, not just for Syrians but also for vital U.S. interests. Chemical weapons have likely been used by President Bashar Assad's regime against civilians, and more than 70,000 people have been slaughtered. The al-Qaeda-aligned al-Nusra Front has gained unprecedented strength on the ground. Iran and its proxy Hizballah are building a network of militias inside Syria. A staggering 5 million Syrians have been displaced from their homes. Meanwhile, cross-border spillover threatens the security and stability of our allies and partners Israel, Jordan, Turkey, Iraq and Lebanon. I know Americans are war-weary and eager to focus on our domestic and economic problems, not foreign affairs. I also know the situation in Syria is complex and there are no ideal options. But the basic choice we face is not complicated: Do the costs of inaction outweigh the costs of action? The events of the past 26 months have convinced me that they do. All of the terrible consequences those against intervening predicted would happen in Syria if we intervened happened because we did not. This conflict will grind on with all of its worsening effects until the military balance of power shifts more decisively against Assad and his Iranian, Russian and Hizballah backers. The U.S. does not have to act alone, put boots on the ground or destroy every Syrian air-defense system to make a difference. We could train and arm well-vetted Syrian opposition forces, as recommended last year by President Obama's national-security team. We could strike Assad's aircraft and Scud-missile launchers. We could destroy artillery and drive Assad's forces from their posts. We could station Patriot-missile batteries just outside Syria to create safe zones across the border. Taking these steps would save innocent lives, give the moderate opposition a better chance to succeed and eventually provide security and responsible governance in Syria after Assad. However, the longer we wait, the worse the situation gets, and the tougher it will be to confront. For America, our interests are our values, and our values are our interests. Nearly two decades ago, I worked with Democrats and Republicans to support President Clinton as he led the U.S. to stop ma** atrocities in Bosnia. The question for another President today, and for all Americans, is whether we will again answer the desperate pleas for rescue that are made uniquely to us, the USA.