Scott Murphy, the Democratic nominee for Tuesday’s hotly contested House special election in New York, now has the backing of someone who had hoped to run against him.

Eric Sundwall — whose bid to qualify as the Libertarian Party nominee in the 20th District contest was rejected by the state elections board — announced Friday that he has endorsed Murphy in his race with Jim Tedisco, the leader of the Republican minority in the state Assembly.

Sundwall drew only 2 percent support among respondents to the latest Siena Research Institute poll. Yet even that tiny constituency, if influenced by Sundwall’s endorsement, could be crucial to Murphy in what is shaping up to be a squeaker of a race.