Jesus would be the complete walking antithesis of the far right American wingnuts who supposedly worship him. The ones who just managed to have abortion banned in certain American states, including in cases of rape. These people are deranged madmen who use the Bible as a mere excuse to justify their hatred, small-mindedness and bigotry.

Yes of course he would , he would also support Universal health care , social welfare and would be appalled at the idea of his followers claiming the carrying of a lethal weapon as in a gun was a “right “ .......Then again I’m an atheist so maybe Jesus really meant wage war , carry guns , ignore the sick and deny social welfare

Nations totally ignore what it says in their sacred books and reinvent god in their own nartional identity

Jesus said blessed are the peacemakers, return not evil for evil, love thy neighbor, and many more things...........................................................

Is/ would Jesus be antiwar?

It's impossible to know what an omniscient being's position would be in every scenario because he would know all outcomes and all possibilities of every action, and some possibilities could never be met without war.

An example might be, a future prophet is only born after his father saved his mother from bomb rubble during WW3. Said prophet would never exist without said war.

We might would label it "omniscient standards" or "omniscient morality", meaning a particular good can only manifest from a particular bad.