A federal appellate court grappled Tuesday with whether the government’s use of voluminous incendiary evidence in a case that led to a Massachusetts man’s 17 1/2 years prison term for supporting al-Qaeda constituted “piling on.”

Tarek Mehanna’s lawyers objected during oral arguments before the U.S. Court of Appeals for the First Circuit to the jury’s exposure to images and videos that Mehanna watched but had no role in producing.