The Plainpalais square in Geneva is papered over with a poster reading, "What would you do if your income were taken care of?" (Denis Balibouse/Reuters)

On Sunday, Swiss voters cast ballots in a national referendum on an idea for helping the poor that brings together European socialists, Silicon Valley geeks and dyed-in-the-wool American conservatives.

The idea is as simple as it is radical. The government would send everyone in the country a check every month, no strings attached. It is known as universal basic income.

Proponents on the left say this kind of system would reduce poverty without the stigma of welfare, since everyone would benefit from it. Supporters on the right say that programs that are available to only those with incomes below a certain level penalize the poor for working more, and that paying everyone a similar amount would get around this problem.

The simplicity of the idea has attracted  support in an eclectic number of circles as the best solution to poverty. Still, advocates must answer a few hard questions. A substantial guaranteed income would be  expensive, while smaller grants might not go far enough for those  in need. Replacing existing public-assistance programs and entitlements with a universal basic income could save money, but could also incite political opposition.

Swiss activists left these questions for a later discussion. They had floated the idea of a generous monthly grant of 2,500 Swiss francs (about $2,600), but the measure — which was rejected by voters, only 23 percent of whom voted in favor —  would have only amended the country's constitution, leaving lawmakers the task of deciding how to design a universal basic income and how to pay for it.

"We expected around 15 percent," said Che Wagner, a spokesman for the campaign. "I'm really surprised how positive the result is."

A more thoroughly developed proposal in the United States reveals some of the compromises that would have to be involved in guaranteeing every citizen a monthly check.

Charles Murray, a controversial social scientist at the American Enterprise Institute, has long advocated for a generous basic income as a replacement for programs such as Social Security. He renewed the debate with a column in the Wall Street Journal last week.

Murray's grant would amount to $10,000 a year for every adult citizen over the age of 21, along with an additional $3,000 dedicated to health insurance. The grant would be worth less for those earning over $30,000 a year, all the way down to $6,500 a year for those making above $60,000.

That is a lot of money, but Murray also proposes eliminating Social Security, Medicare, food stamps, housing assistance, and all of the other programs the country has in place to help the needy.

The average monthly benefit from Social Security is $1,335 for retirees, so most of them would likely receive much less from the government under Murray's plan. Single parents with children would also receive less, because they would lose existing public assistance benefits while having to make do with just $10,000 a year in cash for the family.

Children themselves would get nothing until their 21st birthdays. That's by design, Murray said in an interview.

"For a no-income or a low-income young woman, having a baby provides an income stream that would not otherwise exist, in terms of welfare and in-kind benefits and housing subsidies," he argued. "If you want to have a baby, that’s great. You bear the cost of it. It's your choice."

Likewise, immigrants would get nothing until naturalization.

Yet while some families might lose money on paper as a result of a universal basic income, Murray argues they would still be better off. They could turn to their relatives or neighbors for help, who would have money to share as a result of the basic income grant.

Murray's ideal is a society in which people have enough money to rely on each other for help, rather than on the government. He argues that friends and family are better equipped to figure out how to help a person in need than public servants are, and that society would become more cohesive as a result of mutual giving.

"The key here is not that a person gets $10,000 — but that everybody gets $10,000," Murray said.

Politically, though, that ideal is still a long way off — in the United States or Switzerland.

"It's only the first step in what I'm sure will be a very long debate," said Jacob Kirkegaard, an expert on Europe at the Peterson Institute for International Economics in Washington. "At this point in time, this is still an aspirational dream if you like — even in Switzerland."

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