In the two weeks since a U.S.-led coalition agreed on a surprisingly detailed outline for curbing Iran's nuclear ambitions, hardline elements on both sides have dominated the public debate, giving a false impression the complex negotiation is already in serious trouble.
But a more realistic note has now emerged from, of all places, Congress.
Last week's statement by Iran's supreme leader, Ayatollah Ali Khamenei, declaring all Western sanctions would have to be removed immediately and rejecting detailed inspection, encouraged U.S. critics like Arizona Sen. John McCain to cry failure and accuse Secretary of State John Kerry of misrepresenting the extent of progress.
McCain might ultimately be proven right on substance -- though President Barack Obama was right to criticize him for calling Kerry "delusional" and saying he believed the Ayatollah's version of the talks. But such a judgment certainly seems premature.
For one thing, a final deal has not been crafted, nor written down. And the entire negotiation is beset by complexities, from the details needed to ensure a workable inspection arrangement to the need for accommodating the political situations of various participants, especially Iran.
Against that backdrop, the Senate Foreign Relations Committee has introduced a welcome and somewhat surprising note of bipartisanship that could temper the tone of the inevitable congressional debate and help pave the way for approval of a deal -- provided it contains the appropriate safeguards.
It did so Tuesday in a unanimous vote for a revised proposal to guarantee Congress a voice on the final accord, but under terms that make likely any properly drawn agreement would survive.
The panel's action was a tribute to its new chairman, Sen. Bob Corker, R-Tenn., and its top two Democrats, Sens. Bob Menendez, D-N.J., and Benjamin Cardin, D-Md., who worked together in a manner often lacking these days on Capitol Hill.
By shortening the review period and removing a provision conditioning any agreement on Iran renouncing terrorism, the panel passed a measure the White House accepted, since it seemed likely to have a veto-proof two-thirds majority.
It delays any congressional review until after the June 30 deadline for completing the talks, enabling the administration to tell Iran that Congress won't interfere with the final negotiations, and limits the review period to 30 days, though with some caveats.
Any measure to block an agreement would require 60 votes in the Senate, meaning the 54 Republicans would need some Democratic support. And even if it passed, Obama could veto it, meaning at least 13 Democrats would have to override his veto if all 54 Republican senators voted to do so.
In the end, it might not come to that, though such events as Russia's plans to ship missiles to Iran strengthen the voice of critics, as would any Western compromises needed to reach the final nuclear agreement.
In fact, both sides will likely have to accept compromises: The West might have to ease some international sanctions more quickly than the United States prefers. Iran may have to accept more inspection and a lower level of peaceful nuclear activity than it wants.
There is an underlying irony in the political criticism of Obama's Iran nuclear negotiation -- not to mention his other major international initiative: his outreach to Cuba.
Despite the daring raid that killed Osama bin Laden, Obama has struggled to surmount the characterization -- stemming from an anonymous quote attributed to a White House adviser by The New Yorker's Ryan Lizza -- that he was "leading from behind" by taking a less assertive role in reacting to global turmoil.
That criticism seemed especially appropriate after Obama's inconsistent reaction to the instability that has emerged in several Middle East countries, where he was strongly influenced by his determination to avoid U.S. involvement in another ground war like those in Iraq and Afghanistan. He looked especially weak in vowing to bomb Syria's chemical warfare sites and then backing off.
But "leading from behind" hardly describes Obama's approach to talks with Iran -- and his outreach to Cuba -- where he has taken the initiative to resolve long-festering foreign policy issues.
Judging from the vehemence of some reaction, though, his critics don't like that any better than his prior, less forceful stance.
Carl P. Leubsdorf, former Washington bureau chief of the Dallas Morning News; email@example.com.