Mainly because of his strong anti-slavery views, Welles shifted allegiance in 1854 to the newly established Republican Party and founded a newspaper in 1856 (the Hartford Evening Press) that would espouse Republican ideals for decades thereafter.
Fortrinsvis på grund af hans kraftige holdninger mod slaveri skiftede Welles parti i 1854 til det nystiftede Republikanske Parti og grundlagde i 1856 en avis Hartford Evening Press som støttede de Republikanske idealer i årtierne herefter.