If there's a presidential lesson to be learned in September it's never draw a red line unless you're certain the nation sees red as well — and is standing with you.

At the moment, polls show President Barack Obama and the vast majority of Americans are standing sideways on the issue of a military strike against Syria. A recent survey by the Pew Research Center and USA Today in fact shows the number of adults opposed to Syrian air strikes is growing quickly — from 48 percent to 63 percent since the beginning of the month.

Meanwhile, those who support an attack in retaliation for the gassing of Syrian civilians has remained unchanged at about 28 percent.

The president will have an opportunity to win public — and Congressional — support tonight during his nationally televised address. (6 p.m. PST.) But he has his work cut out for him.

First, he needs to present clear and convincing evidence that not only were hundreds of innocent Syrian civilians gassed on Aug. 21 but that the regime of Syrian President Bashar al-Assad, without a doubt, was directly behind the attack. Americans have been misled before and are understandably wary of claims that clear evidence exists but cannot be produced for security reasons. If Obama has any hope of building public support, he and Secretary of State John Kerry need to bring something more than "trust us."

Second, the president needs to explain how America can launch a surgical strike that will achieve the dual objectives of punishing Assad for crossing the proverbial line in using chemical weapons without sucking the United States into another full-scale military confrontation in the Middle East.

Meanwhile, claims by Assad last weekend during a Charlie Rose interview that his regime was not to blame for the chemical weapons attack — and his warning that America should "expect everything" in the way of retaliatory action — has only fueled public uncertainty.

Finally, Obama needs to persuade the nation that a military response is the only means for accomplishing the nation's goals and that the United States would have the broad support of a coalition of other countries if it chooses to take that course.

Over the weekend, Kerry claimed that the nations that were ready to support U.S. action were in the "double digits." But he reportedly did not name them.

Winning Congressional support — particularly from House members who are just returning from a five-week summer recess where they've been getting an earful from constituents — also will hinge on the president making his case on these three fronts.

Meanwhile, an unlikely ally may have given the president a way to save face in this no-win scenario. In response to a suggestion by Kerry, Russia called on Syria Monday to hand over its chemical weapons to international monitors, and Syria has responded positively.

The idea seemed to be gaining political momentum from America's European allies. As some fear, this could just be a stall tactic. But any alternative to a U.S. bombing is worth pursing because, at this point, that's the only course of action the public supports.