SAN DIEGO -- Residents will decide Tuesday whether San Diego Mayor Jerry Sanders should keep his job or if wealthy businessman Steve Francis should take the helm of California's second-largest city.

In terms of finances, the race for San Diego mayor has been a David-and-Goliath battle, with Francis spending more than $4 million of his own money to finance a slew of campaign commercials.

Francis founded Carmel Valley-based AMN Healthcare, the largest medical staffing company in the country.

The one-time Republican touts himself as "An Independent Mayor For A Change," pledging to eliminate special interests, cut waste, end "back door" tax increases and protect the environment.

Sanders, the former police chief of San Diego, has had to contend with a more modest war chest of about $426,000.

The mayor has labeled Francis a "world-class hypocrite" for reversing course on a number of positions from his time as a former Nevada legislator and during a failed mayoral bid three years ago.

"Let's not mince words here, Steve Francis is trying to buy this election," Sanders said at a campaign event.

The campaign took a testy tone following an Earth Day debate in Balboa Park when Sanders refused to shake Francis' hand and was heard uttering an expletive.

Francis has accused Sanders of pandering to developers, failing to resolve San Diego's financial problems and not doing enough to bolster public safety and fix the city's crumbling roadways.

"I believe local government should work for the people, not the lobbyists, the downtown political elite and the special interests," Francis said in a campaign message.

Sanders defeated Francis in 2005 in the election to finish out the term of Dick Murphy, who resigned as mayor amid mounting criticism of his handling of the city's ongoing financial problems.

Upon taking office, Sanders faced a more than $1 billion pension debt, a suspended municipal credit rating and ongoing investigations into the city's financial disclosure practices.

Despite making slow progress, Sanders has made some headway in reestablishing San Diego's fiscal stature.

Sanders has slashed the city's workforce and has nearly completed an overhaul of most municipal departments.

The city is nearly caught up on delayed audits of its financial statements and Standard & Poor's recently restored San Diego's suspended credit rating, clearing the way for public bond offerings to pay for long-overdue improvements to the city's infrastructure.

"Infrastructure is being rebuilt, deferred maintenance is being done on roads and highways and city facilities," Sanders said in a campaign message.

"We have been very transparent about our budget and actually have a plan in place to solve a lot of these issues."

Also on the ballot are Eric Bidwell, a freelance graphic designer; James Hart, an environmentalist; and Floyd Morrow, who was on the San Diego City Council in the 1970s.

If no one candidate receives more than 50 percent of the vote, a runoff will be held on Nov. 4.