Underwood hates being in the passenger seat. When things happen, he takes charge and does what needs to be done. You can see this in the very first scene of the show where he comes across a dog that’s been run over. He puts it out of his misery by breaking its neck.
Terror is an attempt by warfighters to affect the decisions of democratic leaders by terrorizing their constituents. Underwood wants his opponents to be more afraid of him than of the terrorists.