"The Soviet Union collapsed without a revolution. A transformation is possible. But in Iran, I fear change will be violent, and the current regime will not go quietly," Issa said.
US President Donald Trump mooted regime change and even killing Iran's Supreme Leader Ali Khamenei at the height of combat amid a 12-day war between Iran and Israel last month.
As a ceasefire took hold, the administration backed away from the hawkish rhetoric but a senior Trump aide said this week that change could only come from within.
Issa, whose constituency south of Los Angeles is home to many Iranian-Americans, criticized Iranian opposition groups and exiled figures, saying their disagreements undermined their goal of toppling Tehran.
"They spend more time attacking each other than working together. That’s a strategic failure. If they were united, I believe regime change would already be underway."
A series of mass protests triggered by the death of a young Iranian woman, Mahsa Amini, in morality police custody in 2022 led to nationwide protests which challenged Tehran's authority but were quashed with deadly force.
Congressman Issa also advocated for intensifying pressure on Tehran, calling for the full implementation of Trump's maximum pressure campaign.
"Take those ships, empty them in friendly ports, and don’t let them sail again," he said, referring to vessels carrying Iranian oil. "Cut off Iran’s oil revenue, and you’ll cripple the regime."
Asked about countries like China that continue to buy Iranian oil, Issa suggested offering alternative energy sources.
"I don’t want to deny China oil, but they shouldn’t get it from Iran. We must make it very expensive for Iran to raise revenue for its oppressive regime."
One of the first steps the Trump administration took against Iran was the reimposition of the maximum pressure campaign from his first term which aims at halting Tehran's oil revenues.
But in June, Donald Trump announced China could continue to purchase oil from Iran.
Turning to a bipartisan bill that would allow Israel access to advanced US military technology such as stealth aircraft and bunker-buster bombs, Issa was skeptical.
"Our stealth capability is unmatched. If strikes are necessary, we don’t need to hand over those weapons — we can do it ourselves, as President Trump demonstrated," Issa said.
The United States attacked Iran’s three main nuclear sites at Natanz, Fordow and Isfahan on June 24.