I do not think many people believe that the upcoming U.S.-Russian summit in Helsinki will get to the point of a serious discussion of arms control. However, it might provide an opportunity to address some outstanding issues. The dispute about the INF Treaty is definitely one of those.

We are now in the fifth year of the controversy and, unfortunately, we are not getting closer to finding a way out of this situation. One idea, however, keeps being mentioned in various discussions and policy papers - one-time inspections that would demonstrate that neither the Russian 9M729 cruise missile nor the U.S. Mk-41 launchers deployed in Romania violate the treaty terms. Something along the lines of "You show me your observable differences and I will show you mine."

It's a perfectly fine idea and it is understandable that it has support of the arms control community. Unfortunately, the inspections, even if they can be arranged, are unlikely to solve the issue. In fact, they would complicate the situation even further. To see why this is the case, we need to step back and look at what we know about the alleged violations.

Even though the United States still refuses to reveal any specifics about its accusation on non-compliance, there are some things that we can say with fairly high certainty. We know the designation of the missile, of course - it's 9M729. It is also a reasonable assumption that the missile is some version of the Kalibr sea-launched cruise missile, which, being an SLCM, is perfectly treaty-compliant despite having the range of more than 500 km.

Now to the 9M729 itself. I had a number of posts about the missile - the two more recent ones were in July 2017 and in December 2017. What follows is essentially a summary, although I can say a few things with higher confidence now.

Most importantly, there was no "smoking gun" - the 9M729 missile itself has not been tested to the INF range (which is between 500 km and 5,500 km). This is probably the reason why Russia is so puzzled by the U.S. accusations - this was never intended to be a violation and Russia apparently genuinely believes that it is in full compliance with the treaty.

Now, we know that the fact that the missile was not tested to the INF range doesn't mean much. It is the "range capability" that matters. Here is where the parties diverge - the United States believes it has non-refutable evidence of 9M729 having the INF range capability, while Russia appears to deny that the missile is capable of flying farther than 500 km.

So, imagine that Russia agrees to conduct an inspection and shows the missile to U.S. inspectors. The most likely outcome of that demonstration is that the United States will say that their analysis was correct that 9M729 does have the INF range capability. Given that U.S. experts have already reached that conclusion without seeing the actual missile, I don't see how they would reverse that judgement once they have a chance to inspect 9M729 up close. Russia, of course, would insist that the missile does not have the range, but since "range capability" is not a very well defined concept it would be really difficult to win this argument on technical grounds. At best, the parties will go back to square one, each insisting on its interpretation of the data. More likely, though, instead of showing that the missile is treaty-compliant, Russia would give the United States hard evidence to prove its case.

Another problem is that Russia cannot really afford to admit that the 9M729 has compliance issues. One would think that since only two or so 9M729 battalions have been deployed so far, Russia could offer to destroy those and put the issue to rest. That, however, does not seem to be an option, since Russia apparently tested the missile from a standard Iskander-M launcher. Even though the actual 9M729 launcher is different - it is said to be larger - from the point of view of the treaty Iskander-M launchers are "tainted" and a true return to compliance would require eliminating all of them. This is not something that Russia would want to consider.

So, not only an inspection is unlikely to resolve anything, for Russia it would be an extremely risky move. As would be anything that might look like admitting the violation.

By all indications, Russia has never intended to violate the INF Treaty or circumvent it by covertly deploying a missile with prohibited range. As far as I know, nobody made a conscious decision to do anything that would not be treaty-compliant. Russia stumbled into this crisis largely through poor oversight of its defense industry and a bit of overconfidence in its ability to convincingly defend its case. U.S. politics played an important role too - it is clear to me that had it not been for the pressure on the Obama administration from the Republicans things would have been done differently. Also, in my view the Obama people made a serious mistake by dealing with the problem the way they did - not telling Russia what it is accused of and demanding that Russia must own up to the violation before any discussion can begin.

The Trump administration has fully subscribed to that approach and, according to Russian officials, insists that Russia must repent before anything can happen. Things are further complicated by the fact that there are people in the United States who would not mind using this situation to get out of the INF Treaty (as long as Russia gets the blame). INF compliance is also a convenient issue for those who oppose bilateral arms control. So, things are not looking bright for the INF Treaty.

At the same time, both Russia and the United States maintain that they remain committed to the treaty and want to preserve it. If that commitment is genuine, which it appears to be, it could provide a very small window of opportunity. About the only way the inspections might work is if the parties agree in advance that they will put the matter to rest - Russia will produce the missile and the United States will agree that it is satisfied with what they see and declare the issue closed. This, however, would require a level of trust that does not seem to exist today. And it would mean that the United States will effectively admit that its assessment of non-compliance was wrong. I don't really see this happening.

If Russia really wants to get out of this corner, it could offer to admit the violation and agree to eliminate the disputed missiles and launchers. Not exactly something that I would expect it to do, but theoretically this might be an option. There is the issue of the Iskander launchers, of course, but here an agreement might be possible as well - Russia could demonstrate that the launcher that was used in those 9M729 tests is different from a standard Iskander launcher. The differences do not have to be "functionally related" - there is a precedent in the START Treaty when a red box attached to a launcher was the only thing that distinguished an RS-24 launcher from that of Topol-M. This kind of solution, however, would also require a certain degree of trust between the parties.

My guess is that the best that can come out of the Helsinki summit is a joint statement to the effect that the United States and Russia confirm their commitment to the INF Treaty and agree to work to resolve the differences. But even that would be difficult to expect these days.