The Republican Party has throughout most of its history been far more concerned than the Democratic Party with the vital work of expanding the franchise.
Founded by militant abolitionists, many of them radicals who had fled Europe after the failed revolutions of 1848, the Grand Old Party was in the forefront of the fight to allow freed slaves in the South and landless immigrants in the North to cast ballots. Radical Republicans secured the enactment in 1870 of the Fifteenth Amendment, with its declaration that "the right of U.S. citizens to vote shall not be denied or abridged by the United States or by any State on account of race, color, or previous condition of servitude."
Republicans controlled the US House and Senate when the Nineteenth Amendment, expanding the franchise to include women, was finally submitted to the states. Indeed, Republican senators had to overcome a Democratic filibuster to advance the cause of women's suffrage.
It was a Republican president, Richard Nixon, who wrote to Congress in 1970 expressing his strong support for a constitutional amendment extending the right to vote to 18-, 19- and 20-year-olds.
The history of the Republican Party when it comes to voting rights has been a proud one. But it has been diminished in recent years, as the party's governors and legislators have moved in states across the country to enact anti-democratic Voter ID laws that are, as the League of Women Voters, Common Cause and other groups suggest, nothing more than crude voter-suppression schemes.