The 1805 impeachment of Samuel Chase had a profound effect by helping to establish that judicial impeachment should be confined to cases of alleged corruption or other illegal conduct, while also imposing an unofficial taboo against justices engaging publicly in partisan activity. "After that, no one was impeached for the way they decided cases, but justices stopped giving political opinions, " said UVA law professor John Harrison, who served on a Justice Department commission that studied the issue of impeachment.