When does free speech cross the line into breaking U.S. anti-terrorism laws?

Charlotte Kates co-founded the pro-Hamas organization Samidoun .

She met with leaders of at least two U.S.-designated terrorist organizations at a conference in South Africa .

She also joined members of the groups in online seminars in which they urged the audience to support Hamas and Hezbollah .

Former law enforcement officials have called for the Justice Department to launch a criminal investigation.

U.S. Supreme Court ruled in 2010 that material support laws are unconstitutional.

People convicted of violating the laws can face a maximum sentence of 20 years behind bars.

Kates cited the Humanitarian Law Project case to defend appearing in online panels with members of terrorist groups.

Former FBI assistant director for counterintelligence: "It’s a totality of circumstances".

Samidoun said on its website that it doesn’t have “any material or organizational ties” to U.S.- , Canadian- or European -designated terrorist organizations.

After the 1993 bombing of the World Trade Center , lawmakers passed a statute banning material support to terrorists that includes providing money or property.