As "Implementation Day" for the Iran nuclear deal approaches, the U.S. Congress and Iran appear to be on a collision course that might yet delay or even scuttle the entire deal.

A bipartisan effort is underway in Congress to slap sanctions on Iran for conducting illegal missile tests in October.  And Iran is threatening to renege on the nuclear deal if U.S. restrictions on visas recently enacted by Congress aren't dropped.

Meanwhile, President Obama is resisting placing more sanctions on Iran for the missile tests and wants to grant exemptions to Iranians under the visa waiver program tightened by Congress.

Politico:

The nuclear deal's skeptics are not backing down. Republican lawmakers, along with some Democrats, are expected to press legislative efforts to punish Iran for a range of alleged misbehavior, including its recent testing of ballistic missiles. Proposed legislation tackles everything from the finances of the Iranian Revolutionary Guard Corps to the right of U.S. states to level their own sanctions on Iran. Lawmakers also are likely to try to renew the Iran Sanctions Act, which expires at the end of 2016, early in the year.

Many of the proposals will likely go nowhere and some are symbolic at best. Still, even making some noise on Capitol Hill could send a strong signal to Iran that America is not its friend, no matter how wedded the Obama administration is to the nuclear deal. It also gives Republicans a chance to look strong and bash Obama during a presidential election year.

"One area that we all agree on is the need to be tough on any destabilizing or illegal action by Iran," Senate Foreign Relations Committee Chairman Bob Corker, a Tennessee Republican who opposed the nuclear deal, said during a hearing Thursday. "Failure to impose any consequences on Iran for its violations of U.N. Security Council Resolutions and other destabilizing actions sets a dangerous precedent before implementation of the nuclear agreement, when sanctions are lifted and the leverage shifts to Iran."

Obama administration officials say they are keeping a close eye on all of Iran's activities in the region, including its role in the Syrian civil war. But the officials stress that the nuclear deal must be dealt with separately.

An October ballistic missile test by Iran, for example, violated a U.N. resolution, but not the terms of the nuclear deal, the officials say. The U.S. has pledged to respond to that missile test and a subsequent one reported in November. The nuclear deal's critics, however, are convinced that China and Russia will use their U.N. vetoes to prevent any meaningful punishment of Tehran. Even Obama's allies are worried: 21 Democratic senators wrote a letter to the president last week urging him not to back down on the missile dispute.

Other P5+1 nations are also interested in imposing sanctions on Iran for the missile test.  But any effort in the U.N. Security Council to do so is likely to be vetoed by the Russians or Chinese, or both. 

Of course, that doesn't stop Congress from imposing their own sanctions if enough Democrats will stand up to Obama.  That remains to be seen.

Meanwhile, the president is looking for ways to appease Iran on the visa waiver program:

One issue that has angered Tehran is changes to the U.S. Visa Waiver Program passed into law this month. The changes eliminate the possibility of visa-free travel to the U.S. from citizens of 38 countries, many of them European, if they have visited Iraq, Iran, Syria or Sudan since March 2011; they also bar visa-free travel for citizens of those 38 countries if they happen to be dual nationals of Iraq, Iran, Syria or Sudan, a broad category that includes many people who may have never been to those four countries. The stated goal is to stop terrorists with Western passports from reaching the U.S.

As part of the nuclear deal, the U.S. committed to refrain from policies that are “specifically intended to directly and adversely affect the normalization of trade and economic relations with Iran.” But Iranian officials view the new visa laws as damaging to their economy because they could scare off investors. Iran's foreign minister Javad Zarif has called the new restrictions "absurd." Some European officials also have warned that the changes could violate the nuclear deal.

In a letter to Zarif over the weekend, Secretary of State John Kerry insisted the U.S. was committed to the nuclear deal and that the visa changes would not be a problem because the U.S. could issue waivers or long-term business visas to individuals who might be affected. Obama administration officials also note that the words "specifically intended" in the nuclear deal give the U.S. cover when it comes to justifying the visa laws.

So the president will once again cave in to the demands of the Iranians, who are now apparently dictating U.S. visa policy.

Obama will do anything to save this deal, including conceding even more ground to the Iranians.