Both parties in Congress agree that something needs to be done to prevent Central American parents from sending or bringing their children on the long, dangerous journey to the United States.

Both parties say the solution is to clear up any confusion about US immigration law

And right now, each party is touting its own preferred approach to changing immigration policy — arguing that this would clear up any confusion about US immigration law that may be attracting migrants.

Republicans want an enforcement-based response that would involve mass deportations of child migrants, so as to deter people from coming in the first place. Democrats, meanwhile, have begun arguing that the most permanent solution would be to pass a comprehensive immigration reform bill — and extinguish any hope that people could come illegally now and get legal status in the future.

Both parties seem to assume that Congress can somehow influence how Central American families understand immigration law. Unfortunately, reality is messy and accurate communication is hard. Here's why.

Congress thinks confusion about immigration law is attracting migrants

Republicans, for their part, argue that President Obama has created confusion in Central America about how the American immigration system works by granting deferred action from deportation to young unauthorized immigrants. That leniency, they say, may be enticing child migrants to travel to the United States in the hopes of being able to stay.

What's more, Republicans say, Obama's talk of immigration reform has led migrants to hope that if they arrive in the country now, they'll be granted legal status later when reform passes.

What's surprising is that many Democrats and liberals have accepted this premise — they've just tried to turn the argument on its head. Yes, they agree, immigration policy has gotten awfully confusing (Representative Beto O'Rourke called it "piecemeal" at a hearing on Tuesday). But the only way to fix this, they say, is to pass immigration reform, so that the US sends a clear message about who can come to the country and who can't. And by passing the immigration bill the Senate passed a year ago — which banned anyone who entered the country after 2011 from getting legal status — it would remove the incentive to come now.

Here's how Greg Sargent of the Washington Post phrased the argument:

The better approach, if folks are indeed gambling kids will be granted legal status at some point later, is to pass the Senate bill or something similar now, because that would clarify that those arriving after December 31, 2011 would never qualify for legal status. As it happens, under current law new arrivals will never qualify for legal status. But having this clarified as part of reform - which would get extensive coverage throughout Latin America - would further dispel confusion.

Simon Rosenberg, of the center-left think tank the New Democratic Network, makes a related argument. He believes that migrants are being emboldened to come by inaction on immigration reform: they know that reform will happen eventually, but they know both parties are saying it won't happen until Obama leaves office in 2017. So, Rosenberg says, "people are coming in thinking that they'll be covered under the retroactive date when action finally happens on comprehensive immigration reform in two or three years."

But how much do Central Americans really know about US immigration policy?

One key question, though, is whether Congress can really send a clear message to Central America about its immigration policies — particularly in countries where only 20 percent of the population has Internet access.

According to Elizabeth G. Kennedy, a Fulbright scholar researching child migrants in El Salvador, most migrants and their families don't know very much about the system at all. When asked whether any of the migrants she interviewed were thinking about possibilities for future reform in the US, Kennedy answered flatly, "No."

El Salvador, for its part, only started paying attention to the child migrant crisis a few weeks ago, when President Obama declared the issue a "humanitarian crisis" — and Kennedy suspects that was only big news because the Salvadoran government worried it had implications for their relations with the United States. Before that, she says, "there was very little knowledge — even in the highest echelons of Salvadoran society — "about the system for child migrants in the United States."

"People who have to migrate through Mexico are not the elite — at all," Kennedy says. "So their knowledge of immigration reform is very limited." The families she works with at the migrant return center started asking her about the system for children in the US after the Salvadoran media covered President Obama's comments — but none of them had asked her about it before.

Overall, Kennedy says, fifteen of the 400-plus migrant children she's interviewed knew that the system was somehow different for children in the US than for adults. But some of them thought it was harder to enter the US as a child — and thought they were supposed to lie about their age.

The coyotes smuggling migrants through Mexico and into the US might be responsible for spreading some of this information and misinformation, but it's impossible to know for sure. "I actually imagine that the information changes along the route," Kennedy says. "I wouldn't put it past smuggling networks to let children know, 'Hey, you can present yourself to Customs and Border Protection officers' once they get to the US-Mexico border. They are not telling them ahead of time." On the other hand, the families she's talked to don't trust anything coyotes tell them about the United States anyway.

This means that it might be hard for Congress to send a message to countries like El Salvador by simply enacting immigration reform (or by stepping up enforcement).

It's hard to change the main law benefiting Central American migrants

Kennedy, like other Central American experts, thinks the main factor driving children and families to the United States is their fear of staying in their home countries. "This is not people seeking out a better life for themselves," she says. "This is not people trying to game a system. This is people trying to survive."

As it happens, there are international laws that require countries to take in people in that situation — people who are running for their lives but don't necessarily have legal paperwork. That's why the asylum system exists. And Central Americans have been leaving their home countries to seek asylum elsewhere in North America, including Mexico and Nicaragua, for the last few years.

Sixty percent of Kennedy's interviewees said that they were fleeing El Salvador because of fear of organized crime, gang threats, or violence. That's consistent with other reports estimating that at least half of the current child migrants in the US would be eligible for some sort of humanitarian relief.

From that perspective, the decision to come to the United States isn't based in confusion about immigration reform. It's based in an accurate understanding of how asylum works now. And the asylum system wouldn't be affected by any of the immigration reform ideas now on the table. (There's also a case that changing the asylum system would be a bad idea — and run afoul of international law.)

Rosenberg acknowledges that when thinking about why migrants choose to come to the United States, "we have to be humble" — and not assume that any one reason is 100 percent correct. With humility, it's clear that there's much more to the decision to migrate than what's going on in the halls of the US Congress.