President Obama addressed concerns at his news conference Tuesday that Syria may have crossed his administration's "red line" against the use of chemical weapons, but he remained assiduously vague on what happens if that line is crossed. Obama's comments, shown in a video above, did not appear to break from his past statements on the issue.

"The use of chemical weapons would be a game changer," he said, "and the reason for that is that we have established international laws, international norms that say that when you use these kinds of weapons, you have the potential of killing massive numbers of people in the most inhumane way possible. And the proliferation risks are so significant that we don't want that genie out of the bottle."

Beyond saying again that it would be a "game changer," Obama only focused on reiterating that the United States is still investigating what happened. "What we have now is evidence that chemical weapons have been used inside of Syria, but we don't know how they were used, why they were used, who used them," he said. "We don't have a chain of custody that established what exactly happened."

He discussed the possible U.S. response to chemical weapons only in relation to the risks of reacting without all the information.

"When I am making decisions about America's national security and about the potential of taking additional action in response to chemical weapons use, I've got to make sure I've got the facts," Obama said. "If we end up rushing to judgment without hard, effective evidence, then we can find ourself in a position where we can't mobilize the international community to support what we do. There may be objections even among some people in the region who are sympathetic with the opposition if we take action. So it's important for us to do this in a prudent way."

The current U.S. plan, he said, is to establish "a clear baseline of facts" as to what happened before responding. Obama added, "We've also called on the United Nations to investigate."

This language, particularly the bright red line coupled with vague responses if it's crossed, are consistent with the administration's six previous statements on the issue.

The two times that Obama personally articulated his administration’s red line, he used pretty vague language on what happens if Syria uses chemical weapons. The first time, in August, he said: “That would change my calculus. That would change my equation.” The second time, in March, he said “we will not tolerate” chemical weapons use and “the world is watching; we will hold you accountable.”

So, in the first comment, Obama said only that he would change how he thought about Syria. In the second and more recent statement, he seemed to shift from talking about how the United States would respond to how “the world” would respond. And if “the world” means the United Nations Security Council, which authorizes any multilateral military action such as the 2011 military intervention in Libya, then that’s not much of a threat. Both Russia and China have the ability -- and a demonstrated willingness -- to veto any U.N. action on Syria. There’s little indication that either state has changed its calculus on Syria just because of the U.S. red line.

All of this seems to suggest that the Obama administration has not changed its policy on military intervention generally, where it clearly prefers a multilateral approach, and on Syria in particular, where it's been skeptical that the United States can do more good than harm by intervening. Obama's left the door open for some kind of response, but he seems to be pretty careful about not painting himself into any policy corners or pledging any specific response. As before, he's hinted at the possibility of some kind of United Nations action, but it's not clear what that would be or necessarily even anything more than requesting a formal investigation.