Today’s resignation by Florida Rep. Trey Radel creates another open seat in the House, but it provides little opening for Democrats.  Our House forecasting model previously indicated that the seat was a lock for Republicans: In 1,000 simulations from the model, the Republican won 100 percent of them.  Losing a Republican incumbent lowers that probability to 97 percent — unsurprising in a district in which only 42 percent voted for Obama, and unsurprising in a national political climate that is not providing much of a tailwind for Democrats.

A useful contrast might be Mark Foley, another Florida Republican who resigned in 2006 after sending suggesting messages to House pages.  Democrats were able to win his district in 2006, but his district was more competitive (in 2004, Kerry won 46 percent of that district) and national conditions — a relatively unpopular president, for example — worked in Democrats’ favor that year.

For more on Radel, see Sean Sullivan’s breakdown of the Republicans that might succeed him.