Universal Male Suffrage
It was designed to prohibit discrimination against voters on the basis on race or previous condition of servitude. The main impetus behind the 15th Amendment was the Republican desire to entrench its power in both the North and the South. Black votes would help accomplish that end.
February 26, 1869
Why is it still important?
Not just the wealthy, white men can vote in today's world. All men can vote for the best overall candidate.