Is McCain's "Problem" Akin to Lincoln's?

Regarding John McCain's initial reluctance to go after Obama for his associations (alliances, rather) with people like Billie Ayers or the Reverend Wright, is it correct to conclude that is is based on a "problem" akin to Abraham Lincoln's (one that served him well when and only when the Democrats were divided)?

"He is so honest himself," [Lincoln's friend Joshua] Speed lamented, "that he is slow to believe that others are not equal[l]y so."

Another parallel to the 1850s and 1860s is the Republican's message to the (Southern) Democrats. During the Cooper Union speech of 1860, that followed the 1858 debates between the Republican candidate and the Democrat candidate for the Senatorial election in Illinois, Lincoln had this message to address to the inhabitants of the South, a section that was dominated by the Democratic Party:

…when you speak of us Republicans, you do so only to denounce us a reptiles, or, at the best, as no better than outlaws. You will grant a hearing to pirates or murderers, but nothing like it to … "Republicans." In all your contentions with one another, each of you deems an unconditional condemnation of … "Republicanism" as the first thing to be attended to. Indeed, such condemnation of us seems to be an indispensable prerequisite — license, so to speak — among you to be admitted or permitted to speak at all.