Democratic presidential candidate Barack Obama said today Iran's missile tests proved a need for direct US talks with Tehran while Republican John McCain emphasized sanctions and an anti-missile shield.
Iran's launching of nine long-range and medium-range missiles reverberated across the US campaign trail and both candidates were quick to offer their ideas on forcing Tehran to back down while questioning each other's tactics.
The United States suspects Tehran is developing a nuclear weapon, a charge Iran denies. Neither Mr Obama nor Mr McCain discussed a military option against Iran, emphasizing diplomatic activity instead.
But only Mr Obama saw the need for direct talks with the Iranian leadership, an option for which he was hotly criticized during the Democratic primary campaign by vanquished rival Hillary Clinton as well as by Mr McCain.
"As these tests have reaffirmed, the threat from Iran's nuclear program is real and it is grave. As president, I will do everything in my power to eliminate that threat, and that must begin with direct, aggressive and sustained diplomacy," Illinois Senator Obama said in a statement.
Mr McCain, who in the past has criticized Obama's pursuit of direct talks with Iran as naive, told reporters in South Park, Pennsylvania, that the United States already has ways to communicate its views to Tehran.
"We have lines of communications with the Iranians and they are many," Mr McCain said. "Their behavior ... has obviously not changed."
Mr McCain, whose is trailing Mr Obama in national opinion polls and in surveys of voters in several key battleground states ahead of the November 4th election, attacked Obama for having refused to vote in favor of a Senate resolution that recommended the US State Department declare Iran's Revolutionary Guard a terrorist organization.
The Revolutionary Guard was the organization that launched the missiles, and the United States accuses it of having supplied Iraqi militants with explosive devices used to kill US and Iraqi troops.
"Senator Obama refused to vote. He called it provocative, called it a provocative step. The fact is, this is a terrorist organization and it should have been branded as such," Mr McCain said.
But Obama campaign spokesman Hari Sevugan said Mr Obama has always supported declaring the Revolutionary Guard a terrorist organization.
He said Mr Obama had opposed last year's Senate resolution because its language said the US military in Iraq should be used to counter Iran, "while in fact it has strengthened Iran."
Iran bubbled to the surface of the US presidential campaign as the candidates have been locked in a debate over the sagging US economy and how to proceed in Iraq.
The United States, Russia, China, France, Britain and Germany offered Iran a revised incentives package last month, including assistance to help Tehran develop a civilian nuclear program, in exchange for Iran giving up its nuclear efforts.
The UN Security Council has already imposed three rounds of sanctions on Iran for ignoring its demands to suspend uranium enrichment and other activities.
Mr Obama said diplomacy should be backed by "tougher unilateral and multilateral sanctions."