The Senate appeared close to a deal to unanimously pass an Iran sanctions bill today before an unexpected objection foiled lawmakers efforts.

Democratic aides touted the details of an agreement to increase the economic and diplomatic isolation of the Iranian government earlier in the morning, but by the time Senate Majority Leader Harry Reid (D-Nev.) came to the floor in the afternoon, the deal had crumbled.

Republicans took to the floor to say they didn’t have enough time to review the language submitted by Democrats and that there had been substantial changes to the language of the measure. Two Senators, Minority Whip Jon Kyl (R-Ariz.) and Republican Conference Vice Chairman Roy Blunt (Mo.), said they believed the Senate bill “would be weaker than President [Barack] Obama’s policy.”

Reid seemed genuinely surprised and miffed by the GOP objections, calling the unfolding situation “a classic example of a rope-a-dope,” explaining that he gave the agreement details to Minority Leader Mitch McConnell’s (R-Ky.) office Wednesday and that every time the parties reached agreement, the Republicans “need a little bit more.”

By the time Reid had finished his colloquy with Kyl and Blunt, McConnell took to the floor to ask for more time to work out the language.

“There are Members on my side of the aisle who are concerned that the way the measure is currently crafted could actually be a step in the wrong direction,” McConnell said. “It could have been a drafting error, but what is wrong with sitting down on a bipartisan basis, looking at the language, making sure we get it right?”

The snafu seemed to be over language offered by freshman Republican Sen. Rand Paul (Ky.) that appeared in the final manager’s amendment. The language would explicitly ban the authorization of military force in Iran, a move that was rebuffed by more hawkish Members of the GOP conference such as Sen. Lindsey Graham (S.C.) and Independent Sen. Joe Lieberman (Conn.).

The original Iran sanctions bill was approved unanimously in February by the Senate Banking Committee, but has been updated. The update includes provisions suggested by another freshman, Republican Sen. Mark Kirk (Ill.), who has been a leading voice on the issue this Congress. According to a Democratic leadership aide, the agreement that was rejected on the floor included Kirk’s “anti-Electronic Curtain Initiative,” which would strengthen sanctions against companies that “engage or support censorship in Iran.”

According to the aide, the deal also included changes to strengthen human rights provisions and recognition for the European Union’s stricter rules regarding Iranian banks.

Reid had previously attempted to approve the sanctions bill by unanimous consent March 27.

It is unclear which additional provisions could be added to secure Republican support, considering there is division among the party’s own ranks.