Heresy a Crime?

“If . . . your closest friend secretly entices you, saying, ‘Let us go and worship other gods’ . . . you must certainly put him to death.” Deut. 13: 6-9
Unbelief in Israel was not punishable by death. To refuse to be circumcised (an expression of unbelief, cf. Lev. 26:41; Dt. 30:6; Jer. 9:25-26; Ez. 44:7) caused one to be "cut off" from the religious community (Gen. 17:14). He was excluded from the worship in Israel (Ex. 12:48; Eze. 44:7, 9); he was not executed.

This enticing to follow other gods was not about mere private belief. Israel’s covenant with God was their political constitution. In context, this is talking about a conspiracy to commit treason: