Portman said the United States should impose sanctions again if Iran doesn't capitulate to American demands as part of a nuclear deal.
"If we do not confront Iran, if we continue to negotiate from weakness instead of strength, then Iran will develop a nuclear weapon," he said. "And then the entire international order, the very existence of Israel and millions of lives will be in danger."
Portman’s speech was part of a lunchtime forum on Israel and Islamist extremism. It was put on by the Cuyahoga County Republican Party, to an audience that included members of Cleveland’s Jewish community.
His remarks come as negotiations with Iran continue, and as Israeli Prime Minister Benjamin Netanyahu prepares to address Congress at the invitation of House Speaker John Boehner. The president has said he will not meet with Netanyahu, as the prime minister's election is drawing near.
