Yet in the years since Asa Whitney had begun his agitation the railways of the East had constantly expanded. The first bridge to cross the Mississippi was under construction when Davis reported in 1855. The Illinois Central was opened in 1856. When the Civil War began, the railway frontier had become coterminous with the agricultural frontier, and both were ready to span the gap which separated them from the Pacific.
It has been pointed out by Davis in his history of the Union Pacific Railroad that the period of agitation was approaching probable success when the latter was deferred because of the rivalry of sections and localities into which the scheme was thrown. From about 1850 until 1853 it indeed seemed likely that the road would be built just so soon as the terminus could be agreed upon. To be sure, there was keen rivalry over this; yet the rivalry did not go beyond local jealousies and might readily be compromised. After the reports of the surveys were completed and presented to Congress the problem took on a new aspect which promised postponement until a far greater question could be solved. Slavery and the Pacific railroad are concrete illustrations of the two horns of the national dilemma.
As a national project, the railway raised the problem of its construction under national auspices. Was the United States, or should it become, a nation competent to undertake the work? With no hesitation, many of the advocates of the measure answered yes. Yet even among the friends of the road the query frequently evoked the other answer. Slavery had already taken its place as an institution peculiar to a single section. Its defence and perpetuation depended largely upon proving the contrary of the proposition that the Pacific railroad demanded. For the purposes of slavery defence the United States must remain a mere federation, limited in powers and lacking in the attributes of sovereignty and nationality. Looking back upon this struggle, with half a century gone by, it becomes clear that the final answer upon both questions, slavery and railway, had to be postponed until the more fundamental question of federal character had been worked out. The antitheses were clear, even as Lincoln saw them in 1858. Slavery and localism on the one hand, railway and nationalism on the other, were engaged in a vital struggle for recognition. Together they were incompatible. One or the other must survive alone. Lincoln saw a portion of the problem, and he sketched the answer: "I do not expect the Union to be dissolved,--I do not expect the house to fall, but I do expect it will cease to be divided."