They account for more than 10 percent of Mexico's adults and provide its third-largest source of income, after oil and tourism. But they have no direct voice in politics because they do not live in Mexico.
They are not the millions of workers who have left their homeland, most for the United States, most to escape poverty. Now, many hope Mexico's next presidential election will be the first in which they have a say.
Mexicans in the United States and opposition politicians in Mexico want to establish absentee voting in time for the July 2000 election, which is shaping up as the biggest threat yet to the ruling party's 70-year lock on power.
Whether they will be able to do so is up the governing Institutional Revolutionary Patry (PRI), and supporters of the change accuse party leaders of stonewalling out of fear that Mexicans abroad could cost them the election.
Some advocates of absentee voting say leaders of the ruling party fear Mexicans angry over the economic situation that sent them abroad will vote against the PRI.
Others are even more cynical.
PRI leaders "know they can't be rigging election boxes here in the United States. They just can't afford it," said Jorge Portillos, a San Diego shop owner who headed north 15 years ago. "A true democracy would allow everyone who has a stake in the elections to cast a vote."
Activists are using that kind of sentiment to pressure the PRI to establish voting abroad in time for the 2000 election. They say if it doesn't, it will be reneging on promises of greater demo-cratization.
"If the Mexican electoral system again excludes 7 to 10 million Mexicans who live abroad, then they have not reached and will not reach the level of democratization that they say we will have," said political scientist Jesus Martin Saldana, a Mexican who has spent much of his career teaching in the United States.
"We already make up between 14 and 15 percent of the Mexican electorate. If they exclude us ... it would be like the United States again excluding all of the black population [or] all of the Latino population. This is not democracy."
PRI politicians agreed in 1996 to change Mexico's constitution to allow voters to cast ballots outside their home districts. But they have yet to approve a system for voting by citizens living abroad.
PRI members say "election reform is not a matter to be rushed risk the credibility of the system," said Alfredo Phillips Olmeda, a PRI congressman who heads the Foreign Affairs Committee. "This is a profound topic that we must look at as a proposal to modify the very foundation of Mexico's electoral process. This is not for just one election."
Mexico's Federal Elections Institute said in November that it would be "technically viable" to organize a vote abroad in 2000 and that a poll found 83 percent of Mexicans in the United States would like to vote.
The only thing standing in the way "is simply the political will," said Emilio Zebadua, a member of the institute's governing council.
One complication, though, is the 1996 reform law that said in order to hold voting abroad, the federal government would have to create a National Registry of Citizens and issue a new citizenship identification card. All sides agree that is not feasible before July 2000.
The main problem is that to prove citizenship, Mexicans need documents, and in Mexico up to 15 percent of people lack even a birth certificate, an Interior Ministry official said.
Mexico's civil registry system is being modernized, with new efforts to reach isolated rural regions, but the job will not be done before the next president takes office. And, the official said, "we're not sure whether it will be a priority of the next government."
Opposition parties are not willing to wait and see.
"We will fight to have [voting abroad] implemented in 2000," said Rafael Castilla Peniche, a congressman from the pro-business National Action Patry. "We want this now."
Mr. Castilla has proposed legislation that would allow voting abroad in 2000. Mexicans would be able to register with Mexican embassies or consulates abroad, and present the federal elections card that an estimated 95 percent of Mexican adults already carry.
The elections institute would decide how voting could be done. In the United States, volunteers would be needed to staff as many as 7,000 booths, which could be set up in schools, shopping malls or parks. Voters in areas with few Mexicans would be allowed to mail in their ballots.
To win support from skeptics in Congress, the bill also would require voters to show some link to Mexico - such as a tax receipt or proof that they send money home. Those with dual citizenship would have to declare that they have not previously voted in the elections of another country.
Mr. Castilla hopes the measure will be considered in a special legislative session this year.
It has the support of the four opposition parties in Congress. Mr. Castilla warns that if it doesn't pass, it will be the fault of the PRI - "and the political cost that they will pay will be very high."
Mexicans living abroad "are people who come to Mexico, who could tell their families, their friends, that the PRI opposed this vote," he said.
They also are people with great economic power. Those 7.2 million citizens - all but 100,000 of them in the United States - send home an estimated $5 billion to $7.5 billion a year.
A U.S.-based coalition of Mexican immigrants is rallying support for the movement.
"Well over 40 countries in the world allow people to vote from abroad," said Al Rojas, a coordinator for the 2000 Vote Campaign in Sacramento. "The Mexican government fears its own people and fears their right to bring about this change."
Mr. Phillips, the PRI congressman, insists fear isn't an issue. "There is no indication" expatriates would vote against the PRI," he said.
While politicians debate, Mr. Martin Saldana, the expatriate professor, feels frustration growing. Any further delay, he says, will continue neglect of the millions of Mexicans living outside Mexico.
"The Mexican government, for all of this century, has done nothing to strengthen those ties to give a sense of dignity to its citizens abroad," he said.
"The vote right now means to us a battle to secure and recover citizenship and to contribute our own resources, our own efforts to the democratization of Mexico."