Kazulin, a former presidential candidate, made the remark to RFE/RL's Belarus Service after meeting with U.S. President George W. Bush and Secretary of State Condoleezza Rice in New York.
"Regardless of which candidate wins the [November] U.S. election, Belarus issues will continue to be at the center of attention -- or at least within the zone of attention -- of the next U.S. president's administration," Kazulin said.
"It was noted at the meeting that fundamental human values, human rights, and freedom are the most important things in the position of the United States. Mr. Bush and other U.S. officials said those principles must not be waived."
The gathering over lunch brought together opposition leaders, democracy activists, and other government critics from Cuba to Myanmar and Syria.
Other guests included the Russian opposition leader Garry Kasparov, Cuban journalist Omar Pernet Hernandez; and Sang Hak Park, president of Fighters for Free North Korea.
Afterward, Bush, who leaves office in January, hailed his guests' courage and described them as being "on the front lines of securing liberty."
Washington has imposed sanctions on Belarusian companies and visa bans on some officials over Minsk's human rights record.
Earlier this month it dropped sanctions against two companies following the release of several opposition activists, including Kazulin.
Belarus heads into parliamentary elections on September 28 that Western countries say will be a test of authoritarian President Alyaksandr Lukashenka's commitment to democracy.
International election monitors said last week that the campaign was largely devoid of competition and had failed to give voters a clear idea of the issues at stake.
Kazulin has said the elections will not be democratic or legitimate but that he is still in favor of taking part.
Some 70 opposition candidates have been allowed to run for 110 seats.
Kazulin ran unsuccessfully against Lukashenka in the presidential election two years ago. He was subsequently jailed for his role in the protests that followed Lukashenka's disputed reelection.
He was released last month and earlier this week was named one of three finalists for the European Union's top rights prize.