I'm moving up on seeing some of the other rationales. Although Iran has described Israel's attack as a "declaration of war" (Fox News), Israeli officials have not in their statements declared a war on Iran that I can find, so I'm not sure this part has actually been met: "if another country declares war on Iran". Netanyahu's statement for example is here. So Iran may have in their rhetoric portrayed it as a declaration of war by Israel, but that is not what this question is asking.
So I think it's important not to over-update until we see Iran's retaliation and their rhetoric surrounding it. But at the same it is necessary to update.
Why do you think you're right?
Moving up on some of the recent news, for example: Germany vows to underwrite Ukraine’s long-range missile production
So it's definitely a strong commitment on the part of Germany.
Also, Lockheed Martin has announced a doubling of its HIMARS production is now online, so there will be more of it to go around.
Why might you be wrong?
The clock is ticking, with barely 6 months left. The European countries are building their own supplies, and they may judge that the odds are going up of the US taking care it supplying Ukraine.