You are using an out of date browser. It may not display this or other websites correctly. You should upgrade or use an alternative browser.
alternatehistory.com
Remember, he was elected Governor of New Jersey in 1877 (and not all that narrowly) https://en.wikipedia.org/wiki/New_Jersey_gubernatorial_election,_1877 and he did get two votes on the first ballot for the presidential nomination at the 1880 Democratic National Convention. https://en.wikipedia.org/wiki/1880_Democratic_National_Convention In a deadlocked convention, you can't be sure he couldn't prevail, and with parties so evenly divided in the Gilded Age, it is conceivable he could win in November, carrying all the states Hancock did in OTL plus New York--which McClellan had come very close to carrying even in 1864 (greatly improving on the anti-Lincoln 1860 vote). And very likely he would not have said that the tariff was a local issue (Hancock's much-ridiculed assertion).
By 1880 much of the earlier bitterness over McClellan would have died down, and probably the only people who would still believe that he had stood for peace at any price in 1864--despite his excplicit statements that there could be no peace without Union--would be partisan Republicans who woulodn't vote for any Democratic candidate, anyway.