That is not an option for Harris now. Under Florida's election laws, even though Harris filed ("declared" her candidacy for the U.S. Senate and provided campaign organizational documentation) for the U.S. Senate rate on 2/21/06, she could have chosen to switch her campaign back to the U.S. House (Florida Congressional District 13) seat which she currently holds. She would have to jumped through a few hoops to do so (like writing every contributor to her Senate campaign a letter offering to refund their contributions), but it could be done. However, since she formally "qualified" (plunked down the qualifying fee and formalized her candidacy) for the U.S. Senate race yesterday, that window of opportunity to run to retain her Congressional seat has closed. In Florida, a candidate can only qualify to run for one office, and must actually resign (effective at qualifying) any other elected position they may hold where that elected position's term of office will conflict with the term of office of the hoped-for elected office (not an issue here, as Harris' congressional term of office ends this year anyway). No fall back positions.