What exactly does this do, other than allow people to say 'they are terrorists, the president made it official'?
Will members of Antifa all still have the same constitutional rights as everyone else? Will the FBI be able to investigate them in a way they couldn't previously?
This depends on if Trump is designating them a foreign terrorist organization or a domestic terrorist organization.
The qualifying factor
appears to be that ANTIFA is a "foreign organization". It is unclear based on my initial research what the definition of a "foreign organization" is.
If they are designated a domestic terrorist organization, the designation appears to be largely symbolic. It would probably get some people to think twice before giving money, or other support to Antifa. It is also a signal to Antifa members that the feds are watching and are going to be bringing charges against Antifa members who engage in terrorism, which hopefully will get them to think twice before continuing to engage in terrorism. Antifa often operates in very liberal cities where law enforcement policies effectively allow them to wreak havoc without consequence. Bill Bar said anyone who crosses state lines, or uses the interstate system to commit a crime is committing a federal crime, which means that anyone using interstates to travel or purchase supplies could be charged with a federal crime. He may also extend the theory for people who use the internet to communicate to commit a crime, or the banking system to purchase supplies to commit a crime. I think both of these may or may not hold up in court, but they have the potential to scare people out of continuing to engage in terrorism.
Classifying Antifa as a foreign terrorist organization would have serious, real consequences. Their assets would be frozen, and anyone giving them support would be committing a serious crime.
I would not be surprised if Antifa is receiving money from foreign governments, and foreign people. It is also likely that Antifa's messages are being amplified by foreign governments on social media. I am not sure if either of these would be sufficient to classify Anifta as a "foreign terrorist organization", or if it would hold up in court. If they are classified as a foreign terrorist organization, I suspect a handful of members of congress and some in the liberal media will likely end facing charges.
Pointing a bow and arrow is not something that would justify beating the man. Self-defense is limited to removing the threat of harm, which was about 2 seconds after he was first hit by the mob. Setting his car on fire was completely unjustified under any circumstances.