If Lisa Murkowski wins the drawn-out vote count in Alaska, as now appears likely, she'll become the third person elected to the U.S. Senate by write-in vote, but the first to be elected through that process to a full term.
The first write-in senator was William Knowland of California, elected in a special election in 1946 to fill the unexpired term of Hiram Johnson, who died the year before. Everyone who ran was a write-in candidate, because voters were presented with a blank ballot.
Eight years later, Strom Thurmond was elected in a write-in campaign after Sen. Burnet Rhett Maybank died of a heart attack three days before the political parties were due to certify their candidates for the general election. Democratic party leaders chose a popular state senator, Edgar Brown, nominating him to serve an entire six-year term. Thurmond, also a Democrat, decided to run as a write-in candidate, appealing to voters who were outraged at being denied the chance to vote in a special election. Thurmond summarized the choice this way: "Whether 31 men shall choose the United States senator or whether the people shall choose him."
He carried 37 of the state's 46 counties and won 63% of the vote. Two years later, in 1956, he kept his word by resigning from the Senate to create a vacancy. He then ran to succeed himself and won handily, firmly establishing a political career that made him one of the most influential public servants in South Carolina history.