sentences:  Lincoln had refused to weigh in on his preferred running mate, and the convention chose to nominate Johnson, a Southern War Democrat, in order to boost the party's appeal to Unionists of both parties.The party platform called for the unconditional surrender of the Confederacy, and also endorsed open immigration policies, the construction of a transcontinental railroad, and the establishment of a national currency.By August, Republicans across the country were experiencing feelings of extreme anxiety, fearing that Lincoln would be defeated.