Be the first to like this
When a Senator resigns, the governor of the represented state may immediately appoint a successor. For the House of Representatives, things are more complicated.
See article in the Huffington Post: http://www.huffingtonpost.com/marci-harris/my-congressman-just-resig_b_1660054.html
The Constitution (Article I, Section 2, Clause 4) requires that Representatives must be elected and a special election to be called to fill the seat.
Given the extensive nominating, primary, and general process, districts from which a Member of Congress leaves office -- for whatever reason -- are inevitably left without representation for several months.