According to 8 U.S. Code Subchapter V - ALIEN TERRORIST REMOVAL PROCEDURES via § 1531 and 8 U.S. Code § 1182 - Inadmissible aliens and 8 U.S. Code § 1227 - Deportable aliens - (a)(4)(b), endorsing or espousing terrorist activities or persuading others to endorse or espouse terrorist activity or support a terrorist organization is a deportable offense.
See:
8 U.S. Code Chapter 12 - IMMIGRATION AND NATIONALITY
8 U.S. Code Subchapter V - ALIEN TERRORIST REMOVAL PROCEDURES
8 U.S. Code § 1531 - Definition
(1) the term “alien terrorist” means any alien described in section 1227(a)(4)(B) of this title;8 U.S. Code § 1227 - Deportable aliens - (a)(4)(b)(4) Security and related grounds
(B) Terrorist activities
Any alien who is described in subparagraph (B) or (F) of section 1182(a)(3) of this title is deportable.8 U.S. Code § 1182 - Inadmissible aliens - (a)(3)(a) Classes of aliens ineligible for visas or admission
(3) Security and related grounds
(B) Terrorist activities(i) In general
Any alien who--(VII) endorses or espouses terrorist activity or persuades others to endorse or espouse terrorist activity or support a terrorist organization;
If you do believe that, then deporting them under 8 U.S. Code § 1182 is legal.
-PJ
This regime does not understand the Constitution, and if/when it does understand it, it pleases the regime to ignore it.