Sacramento --

Gov. Jerry Brown vetoed a bill Tuesday that would have made it far easier for farmworkers to join labor unions, 36 years after making history in his first term by signing a law giving the low-wage employees the right to organize.

Brown's veto disappointed and angered dozens of farmworkers who had camped outside his office late into the night Tuesday to try to pressure him into signing the measure. Democratic lawmakers joined supporters in the hallway as they awaited his decision, which came at 11 p.m. in the form of a press release to reporters. The governor refused to come out and talk to the large crowd, despite pleas from Arturo S. Rodriguez, president of the United Farm Workers union.

SB104, by Senate President Pro Tem Darrell Steinberg, D-Sacramento, would have allowed farmworkers to vote for or against unionization by signing a card instead of holding a secret-ballot election - a process called "majority signup election" and also known as "card-check."

Currently, farmworkers can only choose collective bargaining representation through a secret ballot vote, The bill would have let a majority of workers at any company choose union representation by simply signing a petition.

Identical measures have passed both houses of the Legislature numerous times in years past, but were vetoed by former Gov. Arnold Schwarzenegger, a Republican.

Farmworkers and Latino advocates had high hopes that Brown, a Democrat, would sign the bill. The governor has strong ties to the Latino community, which makes up for 37.6 percent of the state's total population and is one of the fastest-growing ethnic groups in California. The governor received 64 percent of the Latino vote last year, according to exit polls.

Brown is also closely allied with unions, who supported the bill and donated $3.1 million to his election campaign last year, according to the nonprofit money tracker Maplight.org - though only $2,300 was from agricultural labor unions. The governor received $343,000 from groups that opposed the measure, Maplight found, including about $5,000 from farm organizations.

The state Assembly approved the measure in May, but no Republicans voted for it. During the floor debate, supporters argued that the measure would protect a vulnerable population - often immigrant farmworkers - from abuse and intimidation by their agricultural bosses.

Proponents often invoked the case of Maria Isabel Vasquez Jimenez, a 17-year-old, pregnant farmworker who died three years ago. According to authorities, she died after her supervisors violated state heat protection laws by failing to provide shade and water as she pruned grapes for nine hours in nearly triple-digit heat in a San Joaquin County vineyard. Two farm supervisors were charged with involuntary manslaughter but only received community service and probation after striking a plea deal with prosecutors.

But Republican opponents said the measure would actually result in farmworkers being coerced by powerful unions and increase the cost of farming. That would prompt farmers it to turn to technology to pick California's crops, they said, instead of hiring people.