Board's statement of a legal standard of probability suffices to establish a violation of the Fifth Amendment when considering the right to counsel in deportation proceedings where the correct standard is that of reasonable possibility of a different outcome.
http://media.ca7.uscourts.gov/cgi-bin/rssExec.pl?Submit=Display&Path=Y2018/D07-05/C:17-1673:J:Rovner:aut:T:fnOp:N:2181672:S:0
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.