With each new vote that is thus secured, it becomes more likely that the president will have sufficient backing from Democrats to sustain a veto of the resolution, which is certain to pass the initial vote thanks to virtually unanimous Republic opposition to the nuclear deal.

This Republican unity has effectively been in place since the beginning of debate on the issue, while 13 Democrats in the Senate and many in the House remain publicly undecided. This imbalance suggests quite clearly that support for the deal is comparatively soft. And this conclusion is borne out by the actual remarks of some supporters, including Markey, who express skepticism about the strength of the deal but intend to vote in favor of it either because of persistent pressure from the president and other Democrats, or because they genuinely believe that it is the best alternative that is currently available.

According to Bloomberg, Markey’s statement in support of the deal specifically pointed to some of its “significant shortcomings” and went on to urge the US government and intelligence community to take measures to compensate for those shortcomings by keeping abreast of illicit Iranian activity and being prepared to put alternative pressure on the regime to discourage those activities.

Delaware radio station WDEL pointed out on Monday that Tom Carper, another Senate Democrat who has come out in support of the nuclear deal, has not allowed that support to diminish his distrust of the Iranian government.

Carper acknowledged that Iran might attempt to cheat on the deal as written. In this sense he agrees with the narratives put forward by opponents of the deal. But Carper appears to have more confidence than these opponents in the willingness of the current US government to confront such cheating once evidence of it emerges.

“If the Iranians cheat, we will know,” Carper said, “and we will catch them at it, and the U.S. alone may re-impose the broad economic sanctions on the regime that’s in place today.”

“If that doesn’t work, we have other options,” he added, referring to the option for military strikes on Iran, which the Obama administration stresses the current deal is aimed at avoiding. The administration has, however, made several comments claiming that that option remains on the table in case it is needed at a later date. But many of Obama’s critics doubt his willingness to utilize that option and feel that his negotiations have already given away numerous concessions to the Iranian regime for the sake of securing a diplomatic pathway at all costs.

According to some reports, the Obama White House has even actively discouraged Israel from launching unilateral strikes on Iranian nuclear infrastructure. The Jewish state is notably wary of the nuclear deal and of a US policy of rapprochement with Iran, and this is a major driving force behind both active opposition to the deal and the sort of skeptical support evinced by many Democrats.

On Monday, speculation emerged that influence from pro-Israeli American voters and political groups may have been a major part of the reason why the Democratic National Committee failed to pass a resolution in support of the nuclear agreement during its summer meeting in Minneapolis this weekend.

Fox News points out that DNC chairperson Debbie Wasserman Schultz is Jewish and represents a Florida district with many Jewish voters, and that she prevented the proposed resolution from coming up for a vote. Reports differ on whether this was an intentional act or merely a result of procedural problems. Wasserman Schultz is among the many Democrats who have not yet announced a position on the nuclear deal.

The lack of a resolution over the weekend did not stop 160 members of the DNC from signing a “Special Letter to the President” which expressed support for his leadership in the nuclear negotiations that concluded on July 14. But obstacles to a broader expression of support point to the incongruous strength of opposition versus support for the deal.

On Monday, an editorial in the New York Post pointed to this incongruity in order to repudiate the current efforts by the Obama administration to utilize congressional filibuster rules to prevent the resolution of disapproval from even coming up for a vote. Obama needs only three more Senate Democrats in order to sustain his filibuster, but if he sways 10 of the remaining 13 to his side he may be able to block the resolution altogether.

The editorial refers to this course of action as obscene, asserting that it effectively undermines the demand for congressional oversight that representatives of both parties pushed for while the negotiations were still ongoing. This betrayal of former intentions is arguably made more serious by the fact that all recent polls show majority opposition to the deal among American voters. A filibuster would thus prevent a formal expression not just of the majority will of the American legislature, but also that of its constituency.

The emerging popular pressure against the implementation of the deal was evidenced on Sunday when about 1,000 people gathered in Boston to urge Congress to overturn the deal, according to the Times of Israel. These demonstrators expressed many of the same sentiments as have been raised repeatedly by pressure groups and congressional Republicans, including comparisons to Nazi appeasement prior to the Second World War and criticisms of the Obama administration for failing to make the release of four captive Americans a precondition for a final deal.

While it is increasingly certain that these popular attitudes will find an outlet through a successful resolution of disapproval, the Fiscal Times points out that they are fueling alternative measures that congressional Republicans and their allies are already considering for when the vote has passed. These include the passage of new pieces of legislation aimed at formalizing the threat of new sanctions for Iranian non-compliance.

It is possible that this would increase Iranian wariness about implementation of the deal, and in any event it would formally express political will to act in opposition to the spirit of rapprochement, thus accomplishing the same basic goal as a resolution of disapproval which does not actually block implementation of the deal.