The don't-mess-with-us approach is intended above all to prevent supporters of Radovan Karadzic from sabotaging the Dayton peace accords.
A Pentagon spokesman said that the aircraft were being deployed "in response to the persistent pattern of vehement rhetoric and incitement to violence being broadcast by Serb radio and television".
The Americans are unhappy that supporters of Mr Karadzic, wanted at The Hague as a war criminal, have failed to keep an agreement to soften their attacks on the Bosnian Serb president, Biljana Plavsic. Ms Plavsic's own track record is less than rosy, but she now backs the Dayton peace agreement, and is therefore backed by Nato.
Control of the media has been a crucial issue since the beginning of the Balkan wars six years ago. Inflammatory television propaganda at that time stoked the aggression and fears of communities who had until then lived peaceably together.
The supporters of Mr Karadzic have remained defiant, even after the Dayton accords were signed two years ago. Earlier this week, they called for a boycott of elections to be held this weekend, though they later withdrew that call. 0n Monday, British and US troops in Bosnia prevented supporters of Mr Karadzic from gathering in the town of Banja Luka, to the fury of the pro-Karadzic Serbs, who called for their supporters to go to Banja Luka "to liberate their leaders".
Momcilo Krajisnik, one of Mr Karadzic's senior aides, had to surrender his bodyguards to Nato protection and himself flee Banja Luka under a hail of stones from Karadzic opponents.
The EC-130 planes, each manned by a crew of 11, are leaving their base in Harrisburg, Pennsylvania in the next two days, in order for the Special Forces planes to fly out from Brindisi over Bosnia during the elections at the weekend. They come under the category of "psychological operations," or "Psyops."
The municipal elections are seen as crucial in the process of trying to rebuild Bosnia. They will be supervised by the Organisation for Security and Co-operation in Europe. At least one international monitor will be stationed at each of the 2,200 polling stations during the vote, and will spend Saturday night there. The elections will not be certified as free and fair until the new local governments are installed.Reuse content