Congress and the president should enact a statute that straightforwardly makes it illegal to publish or circulate materials that support, praise, or advocate terrorism as long as we are still formally at war with al Qaeda and its allies.Schmitt says such a statute could be "narrowly drawn" so that we don't go back to the bad old days of seditious libel. Maybe. But we still don't know which circumstances would cause the United States Congress to end the "war" authorizations spelled out in the AUMF and various other laws. Given the way our leaders have interpreted that so far, it might be a crime to praise the Muslim Uighurs who have rebelled against the Chinese government, or the Chechnyan Muslims who have revolted against rule from Moscow. More likely it might be used to prosecute Americans who praise Hamas. And that's where we start to get into plausibly scary territory.
Generally speaking: We don't know that the "war" will ever end. Which means a statute that sunsets when the war does is basically a statute on the books forever. Wanna draw First Amendment considerations a little more narrowly? You may well have the power to do so. Just don't pretend it's a temporary state of affairs.