On another hand, the US/Russian space programs and teamwork with the ISS is largely separated from the political issues in Ukraine. There is too much to lose on either side.
Even if SpaceX's prices go up with EELV launches, and even if they would never incorporate reusability into EELV launches, they would still be able to offer launches for every possible EELV payload at prices far below ULA's. Anything ULA could launch on any of their vehicles SpaceX could launch on the Falcon Heavy, and many launches (like GPS birds) could happen on the even cheaper Falcon 9.
With reusability, which SpaceX seems to have a good handle on, those costs get slashed, especially the cost of the Falcon Heavy. Any EELV payload could be launched on a reusable Falcon Heavy, even if it meant forgoing crossfeed. Even if the first stages could only be reused twice (a paltry amount) that would lower the cost of a reusable Falcon Heavy to around the cost of a Falcon 9, around $50 million.
Keep in mind that every ULA launcher uses an RL-10 in the upper stage, and that's a $40 million engine. Even at discounted prices simply having an engine that expensive (to say nothing of the rest of the vehicle) on every launch makes it impossible to offer launches as cheap as SpaceX could.
The Delta IV Heavy throttles down the center core during launch and peels away the outer cores first in a sort of "virtual crossfeed" scenario, though this comes at the cost of liftoff thrust.
The only problem with crossfeed for the Falcon Heavy is that it leaves the center core traveling a lot faster and a lot farther down range than the first stage of a Falcon 9 normally would be, which might make it a lot harder to return to the launch site for reusability. However, as a worst-case scenario the Falcon Heavy could be operated without crossfeed with all lower stage cores burning out at the same time, which would reduce payload significantly but the cost savings would probably make it worthwhile even so.
What's a core? Why would the stages burn at the same time? I thought the second stage wouldn't turn on until the first stage is jettisoned?
The Falcon Heavy uses the same "2nd" stage but it uses 3 first stages instead of just one, which are called "cores". Each core is just a Falcon 9 first stage, for the most part. The idea of the Falcon Heavy (similar to the way the Delta IV Heavy works) is that you have three times as many first stages pushing, which leads to increased payload.
With the cross-feed option you end up with effectively a 3-stage launcher. The outer two cores becomes like the first stage, and they are jettisoned when empty, then you have the inner core which now becomes a 2nd stage, and the previous 2nd stage is now a 3rd stage (or just "upper stage", to avoid confusion).
But, as mentioned, when you fly this way the 2nd stage core ends up way faster and way farther away when it's done thrusting, so in the prospect of having it keep around some extra propellant so it can thrust back to the launch site and land so it can be reused becomes much more difficult. But in a worst-case scenario all of the "cores" can be run at the same time, so they burn out the same distance away from land and can each return and be reused (saving a lot of money). You end up with only a 2 stage vehicle (3 1st-stages all running at the same time plus the upper stage) which would decrease performance, but because you recover all of the first stage cores (instead of only 2/3 of them) the cost benefit would probably be worth the payload reduction.
So on the Falcon heavy, is the plan for all three cores to return to the launch pad independently? Just landing a few hundred feet away from each other?
Also, I missed a reusability scenario with Falcon Heavy. You use crossfeed, you return the outer 2 first stage cores, and you dump everything else. This is more expensive than reusing all 3 1st stage cores, of course, but it provides a considerably amount of payload for the cost of essentially an expendable F9 plus the use of the reusable boosters. So you'd get very heavy lift capacity (I dunno, maybe 30+ tonnes to LEO) at well under $100 million, which in the current launch market is a crazy price.
Falcon 9 heavy (no crossfeed) has a first stage and a second stage. But the first stage consists of 3 cores that run in parallel. All three cores start and stop at the same time. So 27 engines start at the pad.
Falcon 9 heavy with crossfeed has sort of two or three stages, depending how you count. Outwards it looks very similar to the no-crossfeed Falcon 9 heavy. The topmost stage is similar to the two already mentioned configurations. The three cores look pretty similar. All three cores start at the pad (27 engines running), but the propellant for the center core's engines is taken from the outer cores' tanks. This means the outer cores run out of propellants quite quickly. They can then be discarded in flight, and the center core starts using propellants from its own tanks. Now it can fly without the dead mass of the outer cores and as a result the rocket can carry a bigger payload.
Why start the core engine at the pad, and not make it a real second stage that starts up only higher? Because then you get more thrust, the engines are not dead weight during early flight.
Some rockets like Titan IV had a somewhat similar parallel configuration but they did not start their center engine except at high altitude.
For the same reason a company that sells a CRUD app might only support Oracle and not other databases. Always working with the same vendor each time reduces technical complexity. People will knee-jerk and say "corruption" but an engineer should be able to at least see where the USAF is coming from.
Given that this is national-security grade stuff, there's also some political and practical considerations. The DOD can't really allow a true market for defense equipment and services. Markets are messy, they go through transition and disruption. That's not acceptable in a national-security context.
Then we should not beat around the bush and pretend we live in a Capitalist system when we clearly must make exceptions for only the private, for-profit contractors that we spend billions of dollars and the majority of the federal budget on.
But if you look at that scenario and smell the possibility for corruption, you're probably not wrong. ;)
Maybe the bidding process was so corrupt and/or pointless that they just did away with it entirely.