Complex sentence: There will be a special election in Illinois's 5th district to replace Representative Rahm Emanuel (D) who will be resigning to assume the position of White House Chief of Staff for United States President-elect Barack Obama.
Split into simpler sentences: There will be a special election in Illinois's 5th district to replace Representative Rahm Emanuel (D). Emanuel is the White House Chief of Staff-designate for United States President-elect Barack Obama.