Since his campaign nearly imploded last summer, McCain has slowly rebuilt and has recently seen improvement in his poll standing, especially in New Hampshire, the site of his 2000 primary victory over George W. Bush. The most recent CBS News survey found McCain tied for second place in the state with 16 percent of support among likely GOP primary voters.
But New Hampshire is a state which has trended away from Republicans in recent years. John Kerry narrowly won the state in 2004 and Democrats have seen gains at the state and local levels in recent years. Perhaps more importantly, McCain faces stiff competition for independents – who make up about 45 percent of the electorate in the state. Those voters are largely credited with spurring McCain's 2000 primary win, at the expense of Bill Bradley, who was challenging Al Gore in the Democratic race at the time.
One of the bigger questions of the New Hampshire contest in 2008 is which race these voters will be attracted to (independents can vote in one or the other on Election Day). Should they trend toward voting the in the high-profile battle between Hillary Clinton and Barack Obama, that could eat into McCain's past base of support.
For a candidate who has angered conservatives in his party on issues ranging from campaign finance to immigration reform, the Union-Leader endorsement is a major coup. Whether it actually translates into any sort of support at the polls is a much more open question.