What is a majority?

The Hill reports (scroll down on the link) on labor activity anticipated as President Obama's team takes charge of the government. One of the interesting changes discussed is a change in election procedures under the Railway Labor Act which governs labor relations for railroads and airlines. In representation elections eligible voters who do not vote are counted as votes against unionization. To win an election a union must get a majority of the eligible voters to affirmatively vote for it. This makes some sense because a union's majority status is  the basis for permitting it to become the representative of the entire bargaining unit including those who object to representation. The interesting thing is elections under the NLRA are determined by the majority of the actual votes cast. It is fair to say the latter method seems to be the one embraced in most political contests and private majority rule contexts. More here.