General Dynamics ( GD) could offer some defense for your portfolio in a volatile trading environment. The stock gained nearly three points Wednesday, closing at $88.93. But don't buy shares just yet: General Dynamics is down fractionally on the year, while its peers like Northrop Grumman ( NOC), Raytheon ( RTN) and Lockheed Martin ( LMT) are all in positive territory for 2008. General Dynamics has also lagged its peers over the past year, gaining 15.1% with dividends, compared with an average gain of 19.5% for the other three top defense contractors. These stocks tend to trade in lockstep, so I would not be surprised to see General Dynamics close this gap in the near term. Given this dynamic, should you buy shares now? While the stock, at current levels, also hasn't kept pace with its peers, General Dynamics is trading still within 6% of its all-time highs. Another factor to consider is the race for the White House next year. So far, the race is wide open, and most of the major candidates have vowed to dramatically reduce the U.S. military's exposure in Iraq. But even if the next president does move troops out of the Middle East, I believe that defense and military spending will remain strong in the foreseeable future, given the continued high level of caution about global terror risks.