When San Francisco voters go to the polls today, they might want to remember a familiar axiom: Be careful what you wish for.

This election for mayor, district attorney and sheriff includes the type of progressive rules campaign reform advocates dream of: Public financing! Ranked-choice voting! Low, low $500 contribution limits! And every one of those reforms approved by a vote of the people or a supermajority of the 11-member Board of Supervisors!

But this election, the first major competition with all those elements in place, shows the continuing gap between the clean, sparkling vision of good government reform and the harsh reality of electoral politics.

And after a full campaign season of experience, it’s probably a good thing for the reformers that all those measures aren’t back on today’s San Francisco ballot.

Take public financing. In San Francisco this year, candidates who agree to abide by a $1.47 million spending limit can collect up to $900,000 of that money in public funds. Anyone who can raise $25,000 from at least 250 contributors can start collecting city money.

The idea is to clear the way for candidates long on good ideas but short on wealthy friends to get into the race and get their message out to the public.

Problem is, the money hasn’t attracted many of those citizen politicians. Of the 11 candidates eligible for public funds, only two – businesswoman Joanna Rees and appointed Mayor Ed Lee – aren’t current or former elected officials, with plenty of hooks into the city’s fundraising machinery. And Lee isn’t taking public financing.

San Francisco, which shares the same financial problems plaguing the rest of California, already has paid out more than $4.5 million to mayoral candidates, with more to come.

The public money also is skewing the race itself. In years past, candidates would jump into the race early, only to see their chances wither. If you’re paying your own bills, even with contributors’ dollars, it’s quickly time to make a choice: stay in and lose expensively or get out quickly and cheaply.

Those moments of economic realism still trim the field in state and national races (see Newsom, Gavin, in the 2010 governor’s contest and Pawlenty, Tim, in the current GOP presidential scramble).

But in San Francisco, if a candidate gets out early, he or she has to repay the public money, money that’s likely already been spent. So you’re left with the aptly nicknamed “zombie” candidates, politicians without a chance, but still in the race because they can’t afford to quit.

Public funding and $500 contribution limits haven’t kept private cash out of the race either. Independent expenditure committees, financed with money from unions, business groups and local powerbrokers have dumped another $1.5 million or so into various mayoral campaigns.

Then there’s ranked-choice voting, which lets voters list their top three picks in a race and then, if no one has a majority, uses a computer to eliminate the lowest-ranking candidates one-by-one, redistributing their second- and third-choice votes until someone has 50 percent plus one.

In a San Francisco supervisor’s race last year, it took 19 rounds of vote redistribution before a winner was decided.

Progressives argue that ranked choice saves money by eliminating the traditional December runoff between the top two finishers. But they also quietly hoped it would give more liberal contenders a boost, since business-oriented candidates typically can raise more money for that short runoff campaign.

That’s exactly what happened in Oakland last year, when former state Sen. Don Perata finished first in the original voting, but ended up losing to Councilwoman Jean Quan when the second-choice votes were tallied.

But in San Francisco, the unintended consequence has been an almost substance-free election. With 16 candidates, including 11 running serious, well-financed campaigns, it’s been virtually impossible to focus on any one person’s plans for the city’s future.

A runoff election though, gives the two surviving candidates a few weeks to make their case to the public, without the unceasing din of a multi-person free-for-all. It also gives voters a chance to vet the plans and promises of whoever is left in the race, especially since they know that one of them is guaranteed to have that job for the next four years.

So that leaves voters in San Francisco – and in the rest of the country, for that matter – in a quandary.

It’s nearly impossible to find anyone aside from political consultants, campaign lawyers and deep-pocketed zealots who are happy with the way campaigns and elections are currently financed and run. But every suggested reform brings its own new set of problems.

Without some magic cure-all, election reform will continue to be a process of looking for the least-bad alternative and then trying to convince voters and politicians to go along.