WASHINGTON – Gaby Pacheco and Felipe Matos, a couple of high-achieving college students from Miami, stand dumbfounded at the corner of 14th and N streets NW.

The plastic side window of their road-weary Ford RV has been slid wide open. It was closed when they parked it at midday a few hours before. Missing from inside: five laptops, a GPS, cellphone chargers.

It’s not the Washington welcome they imagined on Jan. 1 when they began their four-month, 1,500-mile odyssey to deliver a message to President Obama and fire up the next phase of the immigration-reform movement.

Matos, Pacheco and two fellow students on leave from Miami Dade College have walked the entire way. The Trail of Dreams, they call it. The RV is their support vehicle. The computers were how they documented their journey on Facebook and Twitter, gathered 30,000 signatures to bring to the president and marshaled support and shelter along the way.

Pacheco uses her dying cell phone to call police. The dispatcher asks her name. She hesitates.

She can’t help it. She’s reflexively furtive, even after years of training herself to embrace, even proclaim, her identity and peculiar status. The irony of the moment makes her smile. An illegal immigrant calling the police.

“Imagine if we were in Arizona now,” Matos says. “We wouldn’t be calling because we’d be so scared.”

Arizona’s tough new crackdown on illegal immigrants is everybody’s preoccupation as their journey nears its end this afternoon. The Trail of Dreams walk was their idea, but along the way they’ve been supported by groups like the Florida Immigrant Coalition.

The students will lead a march to Lafayette Park, where they will help preside over a rally of expected thousands in front of the White House to advocate for immigration reform. It’s a safe bet all things Arizona will be jeered.

Dozens of marches are planned for today in cities across the country from Los Angeles to Dallas to New York.

SYMPATHETIC FACE

As the national debate grows palpably more bitter and polarized, Pacheco and Matos are the face of the most sympathetic segment of the illegal immigrant population.

Theirs is the image that supporters shrewdly promote to advance their movement, and that even some opponents find difficult to categorically condemn.

They were brought to this country as children — Pacheco at 7 from Ecuador, Matos at 14 from Brazil — and have made the most of American opportunity.

They earned good grades and etched long resumes of extracurricular activities. Matos, 24, who has been academically ranked one of the nation’s top community college students, is studying economics and wants to be a teacher; Pacheco, 25, after earning three community college degrees, wants to start a music therapy program for autistic children.

As illegal immigrants, they don’t qualify for student aid and have trouble affording four-year colleges. And they can’t turn their studies into careers.

“What you see is the all-American girl,” Pacheco says. “Orchestra, cross country , basketball, ROTC.”

Not everybody sees that girl. Her family in Miami is fighting deportation.

An estimated 65,000 illegal immigrants graduate from high school each year and find themselves in similar circumstances.

“Nobody feels good about the situation these kids are in,” says Ira Mehlman, spokesman for the Federation for American Immigration Reform, which advocates for reduced immigration. “It was the decision of their parents to violate the law that put their children in this difficult situation.”

NOT AFRAID, BUT WARY

On Monday, they had reached the outskirts of Alexandria, Va., having trekked through sunshine and snow, crashed in churches and on activists’ couches and told their stories hundreds of times.

Besides Pacheco and Matos, there were Carlos Roa, 22, brought by his parents from Caracas, Venezuela, at 2; and Juan Rodriguez, 20, who was brought from Bogota, Colombia, when he was 6 — and who last year became the only one of the four to obtain legal residency.

“I’m Carlos Roa,” Roa begins. “I’m undocumented, and I’m not afraid.”

Not afraid. But wary. When an American-flag waving delegation of their Alexandria hosts, Tenants and Workers United, briefly marches in a lane of traffic, blocking cars, the trekkers stick law-abidingly to the sidewalk.

THE DREAM ACT

A proposal known as the Dream Act, designed to offer a path to citizenship for students like the trekkers, has bipartisan support in the House and Senate but has been ensnared in the politics of immigration.

The trekkers requested a meeting with Obama. The White House countered by offering a meeting with senior adviser Valerie Jarrett. The trekkers turned it down. They said they had believed in Obama’s campaign promises to support the Dream Act and immigration reform, “so we want to talk to him,” Pacheco says.

They drove into Washington on Wednesday to try to deliver to the White House a sampling of their petition signatures. A uniformed Secret Service agent declined to accept the envelope.

This morning, they will walk the last four miles from Alexandria to the White House.

Organizers of the rally say that “dozens” of protesters who are citizens will commit civil disobedience and risk arrest to call attention to the cause. That’s a step too far for the undocumented trekkers from Miami.

“We don’t want to do anything to make us seem radical,” Pacheco says. “We want to show our love and all our passion and our desire to stay in the country.”