Trend is no friend to Sen. Barbara Boxer, D-Calif.

Rasmussen released a poll today that shows Republican Carly Fiorina leading Barbara Boxer by one point, 48 to 47 percent. That’s if you include “leaners” — people who at first say they’re not sure, but are then urged to pick one anyway.

Especially in the late stages of an election, polls that include leaners are better indicators than those that do not. But here’s an interesting aside about this particular poll. If you don’t include leaners, Fiorina’s lead is 47 to 42 percent. That might be an indication that Boxer’s support is a bit soft.

It’s certainly softer than it has been in past months, and that merits another note on the trend-line in the Rasmussen surveys. Even if you don’t trust a pollster’s methodology, you can learn from his polls because it is usually a consistent methodology. The trend in Rasmussen polls (shown here without leaners) has been that Fiorina gains and Boxer loses support over time. Note that the two have essentially traded places since June.

Carly Fiorina (R) Barbara Boxer (D) Some other candidate Not sure
September 6, 2010 47% 42% 4% 8%
August 24, 2010 43% 44% 5% 8%
August 3, 2010 40% 45% 5% 10%
July 12, 2010 42% 49% 4% 5%
June 9, 2010 43% 48% 5% 5%
May 12, 2010 38% 45% 4% 12%
April 12, 2010 38% 42% 7% 13%
March 11, 2010 40% 46% 4% 10%
February 11, 2010 42% 46% 7% 5%
Opinion: The people – and especially the people of the Tenderloin – want to fund the police

Mayor Breed’s $7.9 million in emergency money to SFPD is not contentious. It’s a Band Aid

I voted for Barry Bonds to get into the Hall of Fame. Here’s why it didn’t matter

Giants star falls short in his 10th and final season of standard eligibility

What does it take to build a skyscraper in S.F.?

Engineering to protect against earthquakes, wind vortexes and, of course, sinking