In1853-1857he was a Whig representative in Congress.
At first a Whig, he joined the Republican party at its formation, and was a Republican representative in Congress from 1859 to 1863.
In 1854-1855, when it became evident that the Whig party in the North was moribund, Seward helped to lead its scattered remnants into the Republican fold.
The heterogeneous elements of the new organization could not be made to unite on a man who for so many years had devoted his energies to purely Whig measures, and he was considered less "available" than Fremont in 1856 and than Lincoln in 1860.
The Whig party on this occasion unanimously followed Burke's lead.