The veto promise comes in spite of publicity for several factors that may be seen as undermining the president’s commitment and his rationale for it. In the first place, several congresspersons have publicly stated that they believe the new sanctions legislation may have sufficient support to override a presidential veto. This may be partly attributable to the fact that the newly proposed Kirk-Menendez bill uses more moderate language than an earlier version of the same bill, thus appealing to a wider spectrum of Iran critics.

These demands are viewed by US lawmakers as wildly out of step with the basic aims of the negotiating process, and this helps to justify the perception that sanctions legislation and similar pressures are necessary to compel Iran to negotiate on more realistic terms. The proposed sanctions bill would not take immediate effect if passed, but would specify that new sanctions will be imposed immediately if Iran does not commit to a compromise agreement.

Although this seems to indicate that the bill would have no effect on Iran as long as negotiations were concluded successfully, the Obama administration still expects that the passage of the bill would lead directly to Iran’s abandonment of those talks. And this matches up with the comments of some Iranian lawmakers who have threatened to resume full-scale uranium enrichment as soon as any new sanctions legislation passes the US Congress.

Of course, these observations do little to alleviate worries that Iran will not show willingness to compromise on a deal in absence of the added pressure of sanctions. This is particularly in doubt in light of the failure to conclude basic aspects of the negotiations prior to the two previous deadlines. Now, amidst the increased pressure from a Republican-dominated Congress and the escalating security crisis in the Middle East, many observers of the talks seem to understand that the upcoming deadline represents the last chance of salvaging a deal.

This sentiment was expressed, for instance, by German Foreign Minister Frank-Walter Steinmeier, according to the Times of Israel. Steinmeir told reporters that all parties appear to agree that the current phase of negotiations is the “decisive phase” and that the negotiations cannot be indefinitely extended.

This apparent expression of urgency did not preclude Steinmeier from describing continued commitment to some Western positions that certain critics of the talks feared would be dropped in light of increasing Iranian leverage. “Iran’s path to nuclear weapons must end unambiguously, verifiably and permanently, and in return sanctions must be lifted credibly and step-by-step,” the German foreign minister said, contradicting Iranian demands that all economic sanctions be lifted en masse upon the signing of a deal.

Still, lawmakers and analysts who are skeptical about the Iranian regime are also fearful of the West giving away too much, and Obama’s firm stance against new sanctions legislations is sure to be viewed by some as evidence of an overly soft Iran policy. Other Obama administration positions further contribute to this perception, including its refusal to raise the issue of Iran’s human rights record at the same time that nuclear negotiations are taking place.

Xinhua News Agency reported on Thursday that the US State Department had effectively reiterated this position on Friday, when department spokesperson Marie Harf said that the US would not make any policy linkages between the nuclear issue and the issue of US citizens imprisoned in Iran.

Former US Marine Amir Hekmati is currently serving a ten year sentence related to accusations of spying. Pastor Saeed Abedini is serving an eight year sentence for practicing his Christian faith and supporting a house church movement in the country. And Washington Post Tehran correspondent Jason Rezaian was reportedly indicted on unspecified security charges this week after being held in detention for nearly six months while the regime presumably attempted to construct a case to justify his political arrest.

White House spokesperson Josh Earnest told reporters that the US had raised this issue “on separate tracks” from the nuclear negotiations, but it is unclear what this entails. The Obama administration has been criticized by members of Congress for lack of action in pursuit of the release of the imprisoned Americans.

But Iran’s broader human rights situation has been variously criticized and raised as a policy issue by other Western governments and by non-governmental organizations. For instance, according to the Assyrian International News Agency, the United Kingdom’s Foreign Office officially raised the issue of the institutionalized persecution of Christians in Iran.

Several persons were arrested during private Christmas celebrations in Iran, and it was revealed this week that at least eleven remain in prison, some of them in undisclosed locations. Such arrests have reportedly become an “annual tradition,” and have been accompanied by crackdowns on non-Muslim religious services conducted in Farsi, as this activity is viewed as encouraging ethnic Iranians to convert, in violation of the country’s religious laws.

Such crackdowns and arrests apparently contributed to worsening of religious rights in Iran over the past year. The country ranks seventh on the 2015 World Watch List, which ranks countries where life as a Christian is most difficult. This puts Iran two positions higher than last year and may be read as the latest indicator that the regime’s policies have not moderated under the government of President Hassan Rouhani.

For critics of the regime, the lack of moderation in domestic affairs suggests a lack of moderation in foreign policy matters as well, and calls into question the Obama administration’s rationale for pursuing compromise and improved relations with Rouhani’s Iran.