PRAGUE, Sept. 26 — To understand just how divisive the proposed American missile-defense radar system is here, talk to Josef Rihak. Better still, talk to both of them.

Josef Rihak, 48, the father of Josef, 18, is a member of the Czech Parliament who in 2003 voted to send troops to Iraq. He is now also mayor of Pribram and coordinator of the League of Mayors Against the Radar, a 35-member group opposed to the installation of the system on Czech soil.

“I have not experienced a topic that would divide the Czech population as much as this radar,” Mr. Rihak said from Pribram, an hour’s drive south of Prague past yellow fields of rapeseed. He needs to look no further than his dinner table for evidence. “I think my son is the biggest ally of the radar in the entire Czech Republic,” he said with a smile.

The younger Mr. Rihak looks both in attire and musculature as if he just stepped out of the Abercrombie & Fitch catalog. He plays American football for the junior national team and would welcome United States troops, especially if they were willing to teach him the finer points of playing defensive end. “I want American people in our country,” he said.