Read Wikileaks, Ethiopia invaded unilaterally because America told them to, they weren’t “invited”.
Of course they were. ICU and AY were negotiating until his convoy was bombed by IED, killing his brother. AY quite the negotiations accused ICU of orchestrating the attack and asked for Ethiopian support.
Doesn't matter if USA had prior intentions to invade Somalia, what matters that AY failed to reach a settlement with ICU and resorted to the nuclear option which is inviting Ethiopia. He later resigned from the government only for ICU leader Sheikh Sharif to take over, but it was too later, ICU become nothing but a shell of it's past and now Al Shabaab are the main destabilizing force against Ethiopia/AMISOM/TFG/FGS