Iowa U.S. Senator Joni Ernst of Iowa says she will run for a second term in 2020.  Ernst told reporters Friday that she would seek re-election. The Republican also said she will support President Donald Trump for re-election in 2020.  The 48-year-old military veteran from Red Oak was elected to the U.S. Senate in 2014 after serving four years in the Iowa Senate. She succeeded Senator Tom Harkin, a veteran Democrat, who retired from politics.  No one has yet announced a challenge to Ernst’s re-election bid, but Iowa Democratic Party Chairman Troy Price said Democrats will put up a fight when she runs for re-election.