The International Brotherhood of Teamsters has endorsed Barack Obama in his tight race with Hillary Clinton for the Democratic presidential nomination. The sought-after union endorsement is one of several received by the Illinois Senator so far in the primary season, and is particularly important given Clinton's perceived support among many blue-collar voters. The Teamsters Union represents about 1.4 million members, including many of the nation's truck drivers. The endorsement could influence voters in the upcoming primary states of Texas, Ohio and Pennsylvania. Each of these states has a sizable number of members in the Teamsters.

But in reality, union endorsements recently have meant less and less to candidates trying to capture votes than was the case decades ago. Can the union force its members to vote for a selected candidate? Of course not. Voters have much more access to other forms of information than just their union bosses, as was the case 100 years ago.

One thing is clear with any kind of endorsement: The more local the race, the more significant and powerful the endorsement becomes. There is less information out there about the local candidates. So any information about who to vote for will be looked at a bit more carefully. The race for the White House is national. There are a lot of public arguments spinning around in the voters' heads before casting their ballots. Nevertheless, it's better for the Teamsters to give a preference now, before the election, than to complain about the president once he or she is elected. This way, the union can expect more from Obama if he gets elected and the public gets a better idea of where the candidate stands on the issues.