Former Speaker of the House Paul Ryan will campaign for a Republican representative who surprised the political world by voting to impeach then-President Donald Trump last year, a development underscoring the fundamental divide between the pre- and post-Trump GOP.

“Tom Rice is a man of principle, a man of conviction, and a leader who always puts South Carolina’s interests first,” Ryan said to media this week. “He is a legislative workhorse with a long track-record of supporting policies that grow the economy, rein in out-of-control spending, and expand opportunities for families and businesses.”

Ryan’s decision highlights the split within the Republican party that has emerged in the years since Trump crashed onto the political scene and won a surprise upset in the 2016 election. Ryan himself ran in the 2012 presidential election as the running mate with Mitt Romney, the latter a longtime and harsh critic of Trump.