Kansas voters have chosen to keep longtime incumbent Pat Roberts in the U.S. Senate in a hard-fought election that helped Republicans secure control of the chamber.

Roberts defeated independent challenger Greg Orman in Tuesday’s election, and Republicans beat enough Democrats in other states to gain a Senate majority.

Roberts told supporters at an election night party in Topeka that he expects to become chairman of the Senate Agriculture Committee. He pledged to be bold, conservative and constructive during his fourth term. He had campaigned by stressing that his re-election was important for Republicans to be able to stand up to President Barack Obama.

Orman had touted his experience as a suburban Kansas City businessman. He had criticized gridlock in Washington and pledged to bring a nonpartisan voice to the Capitol.