Her colleagues greeted the idea with applause. Then she sprang a surprise on them: Two lab technicians waited in the audience to administer drug tests to every state lawmaker. We should set the example, she said.
They nearly trampled one another in the stampede to the door, Del Rincon recalled.
Del Rincon wasn't all that shocked. She was born and bred here in the Pacific Coast state of Sinaloa, home of the drug racket's top leaders, its most talented impresarios and some of its dirtiest government and police officials.
Swaths of Sinaloa periodically become no-go zones for outsiders; the central government abdicated control long ago. By one estimate, 32 towns are run by gangsters.
In Culiacan, the capital, casinos outnumber libraries, and dealerships for yachts and Hummers cater to the inexplicably wealthy.
This is where narco folklore started, with songs and icons that pay homage to gangsters, and where children want to grow up to be traffickers. How Sinaloa confronts its own divided soul offers insight on where the drug war may be going for Mexico, where more than 5,000 people have been killed in drug-related violence this year.
"The monster has lost all proportion," said Del Rincon, who is a member of the conservative National Action Party.
A spunky woman with large eyes and hands that seem to be in constant motion, Del Rincon scans other tables at cafes where she meets people, making sure she knows who is within earshot; she lowers her voice when she names names. Her husband and closest confidant keeps tabs on her whereabouts throughout each day.
Such are the risks of speaking out.
"The narcos have networks meshed into the fabric of business, culture, politics -- every corner of life."
Poppies and marijuana have been cultivated in the mountains of Sinaloa since the late 19th century. For decades, Mexican farmers harvested the crops, and entire dynasties of families dedicated themselves to the trade.
Except for one brutal crackdown in the 1970s, successive governments accommodated the drug trade, even as Mexico became a staging ground for Colombian cocaine headed to its biggest market, the United States.
Back then, one party ruled Mexico. The Institutional Revolutionary Party, or PRI, controlled everything from the smallest of peasant groups to the presidency.
"The state was the referee, and it imposed the rules of the game on the traffickers," Sinaloa-born historian Luis Astorga said. "The world of the politicians and the world of the traffickers contained and protected each other simultaneously."
Slowly, the monopoly started to crack. Parties other than the PRI began to win elections, here and across the nation. Different faces joined regional legislatures, while the PRI struggled to hold on. Del Rincon's PAN won the mayoralty of Culiacan and other posts across Sinaloa.
Finally, the PRI lost the presidency in 2000.
Political pluralism in Mexico may have made room for more firebrands like Del Rincon, but it also fed a free-for-all among trafficking gangs, which began to splinter and compete.