The spasm of spending in this fall's $10 million 19th Senate District campaign purchased many things: an avalanche of mail, a brigade of consultants, a squadron of pollsters and enough television advertising to launch a new brand of shampoo.

But, in the end, the decisive difference may have been something as inexpensive as shoe leather.

Republican Tony Strickland was sworn in this week as the district's new senator, the prize for winning what was not only the most expensive campaign in California this fall but also the state's closest election.

Strickland appeared skinny, almost gaunt. He had the look of someone who had survived a physical ordeal that had brought him nearly to the point of exhaustion. "I did a lot of walking," he explained.

I asked Strickland whether he had knocked on every door in the Santa Clarita neighborhoods that are part of his district. After a thoughtful pause, he answered: "I believe I did."

To be sure, Strickland also logged plenty of miles on residential streets in Ventura and Santa Barbara counties this fall. But it was his work in Santa Clarita that secured his victory.

How a sliver of Santa Clarita came to be included in a Senate district that stretches 132 miles westward to Lompoc is a part of California redistricting lore. When the map of District 19 emerged from behind closed legislative doors in 2001 it was, by design, both hospitable to Republicans and, geographically speaking, relatively clean.

The original district included all of Ventura County, except for Oxnard and Port Hueneme, and all of Santa Barbara County, except for Santa Maria. It would have had a Republican voter registration advantage of 3.6 percentage points.

But some sharp-eyed strategists decided the proposed district was not hospitable enough to the GOP. As a result, three days later, the Democratic-leaning towns of Santa Paula and Fillmore were carved out, and a sliver of Los Angeles County that included a portion of Santa Clarita was pasted on. The new district had a 5.6-point Republican advantage.

Going into the 2008 campaign, Strickland knew that he would be in for a tough race, and he knew that in order to win, he needed to capitalize on the Republicans' Santa Clarita advantage.

The Los Angeles County portion of the district included only 7 percent of the district's 525,000 voters. But those 38,000 voters could be critical. Not only were they decidedly Republican (44.5 percent to 33.5 percent), but the area was also separated from the rest of the district. It was not part of either the Ventura or Santa Barbara media markets, and could therefore be worked in isolation.

Early in the campaign, Strickland secured the endorsements of every member of the Santa Clarita City Council, and he campaigned in the district alongside his friend Cameron Smyth, the city's former mayor who now represents the area in the Assembly.

That focus on Santa Clarita provided Strickland with his narrow margin of victory. Not only did he win the LA County portion of the district, he outperformed the 11-point GOP voter-registration edge there, winning by 15.6 percentage points.

His 4,578-vote margin in Santa Clarita was just enough to overcome Democrat Hannah-Beth Jackson's 3,586-vote margin in the bulk of the district in Ventura and Santa Barbara counties.

Los Angeles County was the only place where either candidate outperformed voter registration. In fact, each slightly underperformed in the other two counties. Jackson finished 2.2 percentage points below the Democratic voter-registration advantage in Santa Barbara County, and Strickland finished 0.6 percentage points below the Republican advantage in Ventura County. Had Strickland merely matched the GOP registration advantage in Santa Clarita, he would have lost.

Strickland wouldn't attribute his victory to his Santa Clarita strategy. "In a race as close as this, every single thing you did made a difference," he said. "If you walk door-to-door and have the wrong message, you still lose."

He said his message of promoting renewable-energy development connected with voters because it was an economic message at a time when voters were most concerned about the economy. "Voters wanted to know what you were going to do for the economy, and we talked about a new way we're going to grow the economy."

But while Strickland hesitates to directly credit Santa Clarita for his victory, Smyth is not so shy about crediting his hometown.

When the Assembly Republican Caucus was briefed on the status of close elections last week, Smyth said, the comment on the Strickland-Jackson race was to the point: "Thank God for Santa Clarita."

— Timm Herdt is chief of The Star state bureau. His political blog "95 percent accurate*" is at http://www.TimmHerdt.com.