The Czech government supports the plan, but the public is skeptical and parliament divided.
The United States wants to station 10 interceptor missiles in Poland and a radar base in the Czech Republic.
On the eve of U.S. President George W. Bush's visit to Prague, people in three Czech villages near the proposed radar site voted overwhelmingly against the hosting the radar.
So far, a total of five towns near the proposed site -- located 70 kilometers southwest of Prague -- have held plebiscites rejecting the plan.
The referendums are nonbinding, but they nevertheless reflect a deep unease among the Czech public about Washington's missile-defense proposal. According to most public opinion polls, approximately 60 percent of Czechs oppose the plan.
Frantisek Sulc, a political commentator for the Czech daily "Lidove noviny" and the co-author of a book on missile defense, says opposition to the radar base is rooted in what he calls "emotional" concerns about foreign domination.
"People are saying we were servants of the Russians for more than 40 years," Sulc says. "After the revolution we though we were going to change that and be sovereign. And now it's like we should be something like servants to the United States."
Bush is hoping to help change these perceptions during his two-day visit.
The U.S. president is scheduled to hold talks on June 5 with Czech President Vaclav Klaus, Prime Minister Mirek Topolanek, and opposition leader Jiri Paroubek.
Topolanek, whose center-right government supports the plan, has resisted calls from Paroubek's center-left opposition to hold a national referendum on hosting the radar.
"The government, the people in the government, the people in the ministries, I mean in the high positions, this elite is pro-American and they are pro-radar.," Sulc says. "They really want it."
Topolanek says parliamentary approval is sufficient -- but even this could prove difficult. His governing coalition controls exactly half the votes in the 200-seat Czech parliament, and will therefore need the backing of at least one opposition lawmaker to gain approval for the plan.
On June 3, Topolanek also said negotiations with the United States would end if the U.S. Congress did not fully fund the project.
Currently, the Democratic-controlled Congress is considering cutting the Pentagon's request for $310 million to begin developing the program.
Czech opponents of the missile-defense plan have expressed concerns about the possible health, safety, and environmental dangers the system might bring. Others worry that it could turn the Czech Republic into a potential target for a terrorist attack.
In an interview on Czech television on June 3, Topolanek defended the missile-defense plan, saying that European civilization "will end without the will to defend itself."
Backers of the plan among the public are also getting organized in preparation for Bush's arrival.
A group called PRO has delivered a letter supporting the missile-defense plan to U.S. Ambassador Richard Graber. The group has also gathered 7,000 signatures in an online petition drive.