Name this great Republican

[AussieMick]

Well done, Roger !!!! Triple marks for thinking outside the square.

I thought that I'd be able to string this out for maybe 2 days. Next few hints would have been ....
He went to prison because of his political views.
He knew someone that painted Lincoln.
He met and argued (?) with Woodrow Wilson.
He was born in the 1840s and was involved in the Great War but never spoke to Lincoln.
He became Prime Minister.