Earlier this week, potential presidential candidate Gov. John Kasich of Ohio visited Iowa to speak about immigration reform. Kasich told Iowans that Congress “needs to get moving on this.” Endorsing legal status for some of the unauthorized population, he added, “We’re not going to just take 12 million people and say, ‘You’re out of here.’”

While addressing those immigrants in the United States illegally remains one of the top issues in immigration reform, candidates like Kasich should rest easy that Republican voters are not anti-immigration reform. Indeed, polls show that only a small percentage of GOP voters favor mass deportation.

Any lawmaker or voter who thinks mass deportation is a viable solution should take into account its tremendous financial costs and its unpopularity with the American people. While Republicans have been tougher on immigration enforcement than Democrats, GOP lawmakers have good fiscal and political reasons to oppose mass deportation.

Earlier this year Ben Gitis and Laura Collins of the American Action Forum published a report on the total costs of mass deportation. They found that the Department of Homeland Security (DHS) would need to spend $100 billion to $300 billion arresting and removing all undocumented immigrants living in the United States, a process they estimate would take 20 years.

Moreover, DHS would have to spend an additional $315 billion over 20 years to keep out new immigrants.

Therefore, a conservative estimate for mass deportation is about $415 billion over 20 years, about $21 billion per year. Gitis and Collins’s high-point estimate totals about $615 billion over 20 years, or $31 billion per year.

The report also finds that removing the millions of unauthorized immigrants would cause the labor force to shrink 6.4 percent, causing the economy to contract by 6 percent, or $1.6 trillion after 20 years.

Economist Raul Hinojosa-Ojeda published a paper in 2013 estimating that mass deportation would reduce U.S. GDP 1.46 percent annually, $2.6 trillion in lost GDP over 10 years, not including the cost of deportation. Moreover, while he found that mass deportation would lead to higher wages for low-skilled native-born workers, wages for high-skilled natives would decline and “widespread” job losses would occur across the country as the economy contracted.

The agricultural, construction, retail, and hospitality sectors would be the most heavily impacted. In 2012 the Economic Research Service at the U.S. Department of Agriculture found that a policy that reduced the number of unauthorized immigrants by about 6 million would reduce agricultural output up to 5 percent and reduce wages for all Americans by 1 percent.

Luckily, the American people oppose mass deportation.

In May, a Pew Research Center poll found that only 27 percent of the public agreed that undocumented immigrants in the U.S. who meet certain requirements should not be allowed to stay. This was the same percentage of respondents as in a January CBS poll. Pew’s poll found that even among Republicans, a majority favored letting these immigrants stay.

Recent polling also suggests Republicans in early primary states oppose forcing unauthorized immigrants to leave. According to a recent poll by the GOP-aligned firm Burning Glass, less than 35 percent of GOP voters in Iowa, New Hampshire, and South Carolina opposed legal status for these immigrants, while majorities in each state supported it.

Furthermore, the polling found that nearly 75 percent of GOP voters in 10 battleground states support legal status, with only 22 percent supporting deportation.

The GOP should not let a tiny but loud minority dictate the conversation on immigration. The American people understand the absurdity of a mass-deportation policy. Deportation would be incredibly costly to the U.S. economy and supporting deportation may be costly in the 2016 election.