How many years does a Justice serve on the
Supreme Court?

Supreme Court justices have life tenure, and so they serve until they die, resign, retire, or are impeached and removed from office. For the 106 non-incumbent justices, the average length of service was 6,203 days (16 years, 359 days).

ummm? is that supposed to be a question or a but this is a reason he won re-election

explanation:

"despite progress in the war, lincoln and most political pundits were convinced that he would lose his bid for reelection in 1864. the country was war weary and the democratic party's nominee, george mcclellan, was likely to negotiate a peace treaty with the confederacy if elected." - loc.gov

c) legal battles last five weeks after the election due to the narrow victory in several states.