On Tuesday night, President Barack Obama will make a speech on national television in hopes of convincing the American people that an attack on the regime of Syrian President Bashar al-Assad is necessary.

The potential strike has repeatedly polled poorly with American voters — something that lawmakers in Congress, who are mulling several possible resolutions, are surely keeping in mind heading into key votes this week and next.

The White House claims it has solid evidence that the Assad regime launched a chemical weapons attack that killed 1,429 people in a Damascus suburb, which seems to be backed up by dramatic photographs and video footage reportedly taken at the scene of the attack. Even before the alleged use of chemical weapons, the war in Syria had killed more than 100,000 people and resulted in more than 2 million Syrian refugees fleeing the country.

Obama will certainly use the carnage to paint a picture of why the U.S. military needs to intervene. Even with his superb oratory skills, however, the president might not be able to sway a war-weary public to get involved in yet another conflict in the Middle East. Here are some challenges the president faces on Tuesday night:

1. Most Americans already think Assad used chemical weapons — and they still don't want to strike Syria
A recent CNN/ORC International poll shows that nearly 80 percent of Americans believe the Assad regime used chemical weapons against its own people. Still, 59 percent of Americans want Congress to vote against any resolution authorizing military action, and nearly seven in 10 voters say a military strike wouldn't be in the interests of the United States.

Unlike former President George W. Bush before Iraq, Obama doesn't have to convince the American people that Assad is using weapons of mass destruction. They already believe that.

Instead, he has to convince them that the United States won't get bogged down in a lengthy war and that U.S. military action would be effective — something that more than 70 percent of Americans don't believe.

2. Republican voters aren't feeling hawkish
The same poll shows that 56 percent of Democrats want Congress to approve a strike against Syria. Most Republicans, however, are leaning towards the position of libertarian-leaning Sen. Rand Paul (Ky.) instead of the hawkish John McCain (R-Ariz.), with only 36 percent of them supporting a "yes" vote.

"Bringing Congress into the equation seems to have added a political dimension to the Syria debate," said CNN Polling Director Keating Holland. "Politics may still stop at the water's edge for most Americans, but Capitol Hill remains a highly partisan environment, even when international affairs are being debated."

3. Americans haven't forgotten Iraq
Back in 2003, Bush was able to convince 64 percent of the American public that the U.S. military needed to put troops on the ground to deal with Saddam Hussein's alleged weapons of mass destruction. Earlier this year, on the 10th anniversary of U.S. military action in Iraq, only 38 percent of Americans thought it was a war worth fighting. Now, Obama has to convince the same people that history won't repeat itself, which is why he was careful to stress during his last weekly address that Syria "would not be another Iraq or Afghanistan."

4. Americans might not be listening to Obama anymore
Big speeches by the president make for great political drama. It's not entirely clear, however, that Americans are paying attention. Obama's last State of the Union address was watched by 33 million people — the worst numbers for the speech since 2000. To put that in perspective, 6.4 million people watched it on CBS, far less than the 21.6 million who tune into the network every week to watch NCIS. Indeed, for years the commentariat has worked itself into a tizzy over whether the president — a consistent media presence who gives an awful lot of speeches — is "overexposed" and losing his influence.

"The president faces strong competition for the public's attention, and most people are not attentive to him," wrote Politico's George C. Edwards III. "A desire to avoid risk and distrust of government make people wary of policy initiatives, especially when they are complex and their consequences are uncertain, as is the case with virtually every proposal for a major shift in public policy and undoubtedly is the case of military action against Syria."

In that light, it's probably no coincidence that Obama's speech was scheduled on Tuesday instead of tonight, when all eyes in Washington (and, let's face it, across the nation) will be on Redskins quarterback Robert Griffin III's comeback on Monday Night Football.