The US is not transferring ATACMS to Ukraine because of concerns about a shortage of tactical ballistic missiles with a range of up to 300 kilometres in case of war with China
The USA is actively helping Ukraine with arms. However, deliveries of some types of weapons are being slowed down as the White House keeps a possible war against China in mind.
Here's What We Know
In early summer 2022, the US and Ukraine officially announced the delivery of M142 HIMARS high-mobility artillery rocket systems. The Ukrainian Armed Forces have been asking for ATACMS tactical ballistic missiles ever since, but the White House has still not approved the deliveries.
The US authorities have found various excuses for rejecting the ATACMS requests. At the same time, no one in the USA has so far officially stated that Ukraine will not receive ballistic missiles for HIMARS. According to The Washington Post, the Pentagon does not have large stocks of ATACMS.
The delivery of tactical ballistic missiles to Ukraine could undermine the combat readiness of the US army. The US Department of Defence fears that after the transfer of ATACMS to Ukraine, the remaining stocks will not be sufficient in case of a military conflict with China.
So far, Ukraine has only used M142 HIMARS and M270 MLRS to launch GMLRS precision-guided projectiles. In 2022, munitions with a range of about 80 kilometres could disrupt the Russians' logistics in eastern and southern Ukraine. Now, HIMARS and MLRS systems are actively used for counter-battery warfare, defeating Russian artillery at the expense of range superiority.
Source: The Washington Post