Direct-mail pieces thrashing state Sen. Perry Thurston Jr., an incumbent in a crowded Democratic primary in South Florida, are linked to a web of political organizations with ties to a prominent Republican consultant.

The mail accuses Thurston, a likely future Senate Democratic leader, of being a closeted Republican and not a progressive, two claims Thurston said are insulting.

But such attacks could prove damaging in the heavily Democratic Senate District 33 in Broward County, particularly when the knock is peddled by a political committee named Progressives, a title that is generally associated with Democrats.