(CNN) - Missouri Rep. Ike Skelton said Tuesday he will cast his superdelegate vote for Hillary Clinton.
In a statement released by the Clinton campaign, Skelton said he is supporting the New York senator because of "her support in rural America, her commitment to National Security, and her dedication to our men and women in uniform."
Skelton is chairman of the powerful House Armed Services Committee and has served in congress for over 30 years. His state narrowly voted for Barack Obama on February 5, though Clinton won 60 percent of his congressional district.
With Skelton's endorsement, Clinton now holds a 22 superdelegate lead over Obama, 259 to 237, according to CNN's estimate. More than 300 superdelegates have yet to make up their minds.
Skelton is the fourth superdelegate to endorse a candidate Tuesday. Earlier, North Carolina Gov. Mike Easley announced he was backing Clinton and Kentucky Rep. Ben Chandler and Iowa DNC member Richard Machacek announced they were supporting Obama.