Long-standing Republican unity on the Federal Election Commission, especially against liberal efforts to expand rules to punish GOP candidates, appears to be in jeopardy with the arrival of a new member who has stirred controversy by voting with Democrats in a key case.

The political fissure was made public last week when the FEC closed a case involving a pro-Trump political action committee and revealed that Republican Commissioner Allen Dickerson sided with all three Democrats to open the investigation in a 4-1 vote in February.