If Cleveland had lost, many Democrats would have blamed Tammany Hall--not without some plausibility:
"There was a great deal of discussion as to what attitude Tammany, after its rebuff at the Democratic convention, would assume toward the ticket. The Tammany leaders appointed a committee to take up the question of endorsing Cleveland and this committee said in its report: "The candidate of the Democratic party having been nominated in the National Convention, following the uniform and unbroken record of our organization, we acquiesce in the will of the majority of the representatives of the party although we believe that will to have been unwisely expressed." The report was adopted, although Grady opposed it and announced his intention of supporting Butler.2 Grady carried out his threat and campaigned for Butler.3 John Kelly and other leaders spoke for Cleveland during the campaign, but they were not at all enthusiastic* On city offices Tammany made no attempt to combine with the other Democratic factions but nominated a straight ticket. The Republicans also nominated a straight ticket, while a citizens' committee nominated a third ticket, which was endorsed by the County Democracy, Irving Hall and the Anti-Monopolists.5 Just before election Tammany sent out circulars lauding its candidates and containing ballots to be cast for city officials, but nothing was said of Cleveland and there were no ballots with the names of his electors.8 In the election Grant, the Tammany candidate for mayor, received 20,000 more votes than Tammany was expected to poll normally, while counting the Republican votes which Cleveland probably received, his vote was 20,000 short of what it should have been. This led to the charge that a deal had been made between Tammany and the Republicans by which Republican votes were cast for Grant in return for Tammany votes for Blaine.1 Tammany accused Irving Hall of having sold out in return for votes for Grace, the fusion nominee."
https://books.google.com/books?id=huQkAAAAYAAJ&pg=PA221
The resulting resentment might have made it harder for any Tammany-backed candidate to get the Democratic nomination in 1888.