A reader makes a common but essential point:

Regarding your take on the Tarek Mehanna case, the trouble I have with comparisons to WWII examples is this war against al-Qaeda has almost nothing in common with WWII, or other wars for that matter.  This isn’t a war involving global powers battling for supremacy.  This is a war against an ideology, and I don’t see how that can be won militarily.  We use our military to chase al-Qaeda from one country to the next in hopes of eliminating them for good.  There is almost no end in sight to this vicious cycle, and in the process we see our liberties and freedoms slowly erode away.

An expert weighs in:

One of the problems with casually throwing around a term like "treason" (as your question seems to do and as Bill Maher most certainly did in the wake of the Al-Awlaki killing) is that it has a specific legal definition and Constitutional restrictions on how defendants may be convicted of treason. As a former federal prosecutor, I can tell you that "treason" is not simply sympathizing with the enemy, advocating for the enemy, or translating the enemy’s vile propaganda (all things Mehanna seemed to do). 

Treason in the Constitution is defined as "levying War against [the United States], or adhering to their Enemies, giving them Aid and Comfort."   There are whole bodies of case law defining those terms.   Even if you can define the acts of Mehanna and Al-Awlaki as treason (and you may have an argument there), the Constitution puts another roadblock in the way, "No Person shall be convicted of Treason unless on the Testimony of two Witnesses to the same overt Act, or on Confession in open Court."  The government could not live up to that burden.   So instead, it prosecuted Mehanna for translating speech. 

For Awlaki, it went even further when it summarily killed him.  The Constitution, in a republic of laws, is non-negotiable.  It will not do to convict people of exercising their constitutional rights to speech (assuming Mehanna was not acting at the direction of Al Qaeda) or due process (in the case of Al-Awlaki) – and then justifying the constitutional intrusion by saying, "well, they were guilty of ‘treason’ anyway." If they are guilty of treason, follow the Constitution and convict them of it under the due process of law.  There are quite simply no shortcuts to Constitutional governance.

Another:

Just a quick note on your earlier reader email in regards to Tarek Mehanna, mentioning Axis propagandists. I'm not familiar with most of the cases there, but citing 200px-Iva_Toguri_mug_shotjustice of prosecuting propagandists. She refused to renounce her American citiizenship when stuck in Japan after the war broke out, risked her life to smuggle food to Allied POWs, and was selected as an announcer for Radio Tokyo by Allied POWs forced to run English-language propaganda, possibly as a bid to subvert Japanese aims by offering transparently absurd taunts and comedy sketches and mostly playing American music for US sailors far from home. Her prosecution was driven by post-war anti-Japanese sentiment, in which the key witnesses were later shown to have perjured themselves under threats from the FBI. She was ultimately pardoned by Gerald Ford. All this is covered fairly well on the wikipedia link above.

Not sure how much relevance this has to the Mehanna case, but I always cringe when I hear Tokyo Rose being presented as an emblematic traitor propagandist when, if anything, she was quite the opposite.