A.T. Robertson Commentary Acts 28:19

"But when the Jews spake against it, I was constrained to appeal unto Caesar; not that I had aught whereof to accuse my nation." — Acts 28:19 (ASV)

When the Jews spake against it (αντιλεγοντων των Ιουδαιων). Genitive absolute again, αντιλεγοντων (αντιλεγω) common verb for speaking against as in 13:45. Clementer dicit (Bengel). "The word is a mild one to describe the bitter enmity of the Jews" (Knowling).

I was constrained (ηναγκασθην). "I was compelled," first aorist passive indicative of αναγκαζω, the very word used of Paul's efforts to get the Christians to blaspheme (26:11) which see. Paul was compelled to appeal to Caesar (see 25:11,12 for this phrase), unless Paul was willing to be the victim of Jewish hate when he had done no wrong.

Not that I had aught to accuse my nation of (ουχ ως του εθνους μου εχων τ κατηγορειν). This use of ως with a participle (εχων) is common in Greek for the alleged reason. The genitive case with the infinitive κατηγορειν is regular. Paul says εθνος instead of λαος as in 24:17; 26:4.