Immigration has loomed larger as an issue in the Republican presidential debates than it does in the minds of most voters. Driven by a minority of activists in their party, the candidates have been drawn into an unhealthy competition to see who can sound the harshest in cracking down on low-skilled illegal immigrants from Latin America.

So far the biggest loser in the competition is the Republican party.

The party is losing out because the rhetoric brings us no closer to actually solving the problem, while driving away voters crucial to the party’s long-term success.

In recent debates, the candidates have argued over who will build the longest and most secure fence along our border with Mexico. Mitt Romney wants it to cover all 2,000 miles, no matter what the terrain or the cost. Michele Bachmann wants to double down by making the fence two-tiered. Before he suspended his campaign, Herman Cain called for the fence to be lethally electrified. Any candidate who expresses any sympathy for immigrants or their children is quickly denounced as favoring “amnesty.”

Conservatives should be friendly to immigration, and the first to seek expanded opportunities for legal immigration. Immigration has been integral to America’s free and open economy. Immigrants embody the American spirit. They are self-starters seeking opportunity to support themselves and their families in the private sector.

Current immigration is driven largely by demand and supply. Immigrants come when there are jobs available that not enough Americans are able and willing to fill. That’s why immigration rates, legal and illegal, tend to fall when the economy is struggling, and to pick up as the economy grows. Immigrants stimulate job creation for natives by promoting investment, creating new products and services, and increasing demand for housing and other goods. Immigration keeps America demographically healthy while other, less open Western nations struggle with declining workforces.

Study after study confirms that immigrants help to boost the productivity and incomes of native-born Americans. A 2009 Cato Institute study by Peter Dixon and Maureen Rimmer calculated that legalizing low-skilled immigration would boost the collective income of U.S. households by $180 billion per year. A new American Enterprise Institute study by Madeline Zavodny finds that an increase in visas for both high-skilled and less-skilled foreign-born workers actually creates a net increase in jobs for native-born workers.

Contrary to fears stoked by talk radio, immigrants do not fuel an increase in crime. In fact, immigrants are less likely to commit crimes than their native counterparts. They are too busy working and don’t want to jeopardize their residency in the United States by getting into trouble with law enforcement. That helps to explain why crime rates have been dropping for two decades in Arizona and across the country even as immigration rates have been rising.

If legal immigration were expanded, the kind of workers now sneaking across the border illegally would instead enter legally through established ports of entry. We know from the Bracero program in the 1950s that an increase in guest-worker visas led to a sharp drop in illegal traffic across the border. With far fewer workers entering illegally, the Border Patrol and local law-enforcement officers could concentrate their resources on apprehending real criminals.

Immigrants come to America to work, not to live off the welfare state. Their labor-force participation rates exceed those of native-born Americans. U.S. law bars immigrants from collecting welfare for at least five years after they arrive.

Critics of immigration routinely exaggerate the cost of emergency-room care and public education for immigrants and their families. The cost of government services used by illegal immigrants is a small fraction of what government spends on middle-class entitlement programs, corporate welfare, and farm subsidies. If conservatives are worried about social spending on immigrants, their aim should be to wall off the welfare state, not our country.

Immigrants do not undermine American culture, they enrich it. Immigrants come because they appreciate the freedom and economic opportunity that has traditionally defined our country. Like waves of immigrants in the past, today’s Hispanic and Asian immigrants are learning English, and their children and grandchildren are overwhelmingly fluent.

In April 1980, when Ronald Reagan was competing in the presidential primaries, he rejected the building of a wall between the United States and Mexico: “Rather than talking about putting up a fence, why don’t we work out some recognition of our mutual problems? Make it possible for them to come here legally with a work permit — and then while they’re working and earning here, they pay taxes here. And when they want to go back, they can go back. And open the border both ways by understanding their problems.”

If a Republican presidential candidate said such a thing today, he or she would suffer withering criticism for being soft on illegal immigration. Instead, we hear Reagan’s successors talk about implementing national ID cards, imposing intrusive regulations on the labor market, raiding farms, factories, and restaurants, and harassing small-business owners trying to survive in this tough economy, all in the name of chasing away hard-working immigrants.

In the past two decades, spending on border enforcement has skyrocketed more than six-fold, and personnel at the border five-fold. Yet the mantra of many Republicans has been to throw more money at the problem while rejecting any fundamental reform of the immigration system itself.

The predominant GOP view on immigration is not only bad policy but also bad politics. Hispanics are now the largest minority group and the fastest-growing voting bloc. Ronald Reagan understood, as did George W. Bush, that millions of Hispanics are friendly to the Republican message of entrepreneurship, opportunity, and family values. The demeaning rhetoric about unauthorized immigrant workers that emanates from the right is interpreted by many Hispanic citizens as a putdown of their culture. Republicans thus risk alienating potential Hispanic supporters, as well as more moderate non-Hispanic voters. With the long-term demographic changes already in motion, an anti-immigration Republican party will find it more and more difficult to win elections.

Spending billions more each year to enforce a fundamentally unenforceable law is not the conservative answer to illegal immigration. Immigration law needs to be changed in a way that better serves our economic needs, protects our security, and affirms our best values as a nation.