President Obama and Congress face no good options when it comes to taking action in Syria.

The case for launching a strike is that the Syrian government’s use of chemical weapons should be punished so that they are not used in the future — by Syria or anyone else.

Doing nothing would send the opposite signal and might also telegraph U.S. weakness on the international stage.

Yet, there is no guarantee a strike will prevent the future use of chemical weapons or that it will bolster U.S. prestige. It could also draw the U.S. further into a messy conflict.

Here are some of the reasons why the decision is so difficult:

U.S. credibility
President Obama put more than his own prestige on the line when he asked Congress for authorization to strike Syria.

Battered by the wars in Iraq and Afghanistan, the world is watching to see whether the U.S. will engage in Syria or shrink from the scene.

If the U.S. is unwilling to intervene in Syria after its president declared the use of chemical weapons a “red line,” leaders in the Middle East and elsewhere will reevaluate America’s standing.

That’s one reason Sen. John McCain (R-Ariz.) has said it would be disastrous for the U.S. not to go forward with a strike.

Many members of Congress are conscious of this dilemma. While they may think Obama made a mistake by setting out the red line, they don’t want the U.S. to be seen as creeping toward isolationism.

Even for Republicans who would relish seeing Obama humiliated, that is likely a tough pill to swallow.

Yet there are plenty of other members who do not want the U.S. to be pulled into action because of Obama’s comments.

Syria’s civil war
Those backing military action against Syrian President Bashar Assad’s government for its use of chemical weapons don’t necessarily want to become a player in Syria’s civil war.

A complicated web of rebel groups is fighting Assad, and some of them are enemies of the United States. Al Qaeda affiliate Jabhat al-Nusra is among the most prominent groups battling Assad.

Many lawmakers are concerned Syria could turn into a repeat of Afghanistan, where the U.S. provided weapons to the mujahedeen fighting a Soviet invasion. The intervention arguably paved the way for the Taliban and the Sept. 11, 2001, attacks.

Ideally, Obama hopes that military action can weaken the regime just enough to usher in a political transition. In reality, striking that balance will prove an extreme challenge.

Chemical weapons
Any military action is ostensibly aimed at dissuading Assad from using chemical weapons again, and supporters of intervention have argued that allowing last month’s attack to go unpunished would set a dangerous precedent.

But it’s unclear that a response limited in scope and stalled by congressional deliberations will do anything to dissuade Assad.

His forces have already fled possible target sites and allowed the Syrians to bolster their defenses.

Successfully damaging the government’s capabilities also carry risk; if Assad feels boxed into a corner by the U.S. military, he has little incentive against launching another sarin attack. And while Assad has thus far maintained control over his weapons cache, according to American intelligence forces, his willingness to transfer those weapons to terror groups or anti-American allies in the region could increase under duress.

Wider war
Further use of chemical weapons runs the danger of quickly escalating the Syrian conflict.

While President Obama insisted Tuesday that “this is not Iraq, and this is not Afghanistan,” Secretary of State John Kerry told senators later in the afternoon that “if Syria imploded” and chemical weapons might fall into terrorist hands, he did not want to “take off the table” boots on the ground.

Syria’s conflict is also a microcosm of and proxy for the greater regional struggle playing out across the Middle East.

Assad’s regime is seen as an important ally of Tehran, while rebel groups have been closely aligned with Saudi Arabia. Doing nothing aides Iran in that regional struggle.

Israel
The administration has argued that if Syria’s chemical weapons use goes unchecked, Assad’s forces or other countries in the region might next turn those weapons on Israel.

On Tuesday, the American Israel Public Affairs Committee (AIPAC) announced its support for military intervention in what could be a crucial moment for the congressional debate.

Still, some anti-war Republicans say that strikes against Syria could prompt Assad or the Lebanese militia group Hezbollah to attack Israel in response.

Israel has remained largely silent on possible strikes, although indications are that leaders there would like to see the U.S. take action.