As we have diplomatic ties and some trade with Umbra, that nation under attack could possibly mean that we might be Osea's next target in their war. Plus, we cannot afford to lose one of the 2 allies of NR. We sadly has to take the decision to launch a SSTO-boosted MIRV attack on high value targets in Osean territory such as airfields, military bases and industrial cities.
Plus, we can use this as opportunity to slow down the rate Scratchian projects are stolen by Osea, as well as forge closer ties with Umbra.