Clad in red jackets, khaki pants, and workboots, 265 City Year volunteers greet 10,000 students each morning at nearly two dozen Boston schools with cheers and clapping — a grand gesture to show they are welcome. Then the volunteers hit the phones and call those who didn’t show up.

This laser-like focus on attendance has played an instrumental role in boosting attendance rates at many schools, and along with it a student’s chance for success. But all of it is now in jeopardy under President Trump’s budget proposal.

Trump is calling for the elimination of the Corporation for National and Community Service, including its signature AmeriCorps program, which provides more than $48 million in funding to City Year and a host of other programs in Massachusetts, including Citizen Schools, Jumpstart, YouthBuild, and Playworks .

Heads of the program said the cuts would be devastating and could cause them to dramatically scale back initiatives that combat bullying and childhood obesity, and boost early literacy, among other issues. In Boston alone, more than 1,400 national service members are working in more than 320 locations.

“If AmeriCorps is eliminated, it would be a disaster for public education, especially in cities,” said Michael Brown, chief executive officer and co-founder of City Year, which serves more than 200,000 students in 28 cities nationwide. “The young people volunteering are giving their all. They are up at the crack of dawn. To say no to all that citizen energy would be a travesty.”

During the past school year, Boston students coached by City Year increased their average daily attendance rates, and most students saw improvement in their reading and math assessments, the organization said.

The budget ax would be carrying particularly heavy weight in Massachusetts. It was here while Bill Clinton was running for president that he came across City Year, which inspired him to create AmeriCorps in 1994, a program that now sends 80,000 volunteers into communities nationwide every year.

Brown issued “A Call to Action” Thursday night to galvanize organizations and the public to band together to fight the proposed cuts. Brown, like other supporters, pointed to a 2013 Columbia University study that found “every dollar invested in national service generates almost $4 in returns to society in terms of higher earnings, increased output, and other community-wide benefits.”

In justifying the proposed cuts, the Trump administration argues that it aims to defund programs that don’t work. The president’s budget chief, Mick Mulvaney, scoffed at funding afterschool programs, for instance, saying there’s “no demonstrable” evidence that they work.

That struck a nerve with Megan Bird, executive director for Citizen Schools, an afterschool program that uses 64 corps members in Boston, Chelsea, and Salem.

“He’s dead wrong,” she said. “There’s a mountain of data that says we are making a difference in the lives of the young people we are serving.”

Citizen Schools says its program adds the equivalent of three additional months of learning.

The Corporation for National and Community Service defended the programs it funds, saying it “supports some of the best solutions from outside Washington, where ordinary citizens are contributing their own extraordinary ideas.”

“The more than 325,000 citizens serving through AmeriCorps and Senior Corps programs are preparing today’s students for tomorrow’s jobs, reducing crime and reviving cities, connecting returning veterans to jobs, fighting the opioid epidemic, supporting seniors to live independently and with dignity, making college more accessible and affordable, and helping Americans rebuild their lives following a disaster,” Samantha J. Warfield, the agency’s spokeswoman, said in a statement.

AmeriCorps provides funding for programs to recruit and train volunteers, who receive a stipend. Volunteers are eligible for college scholarships.

Programs also raise matching funds that at least double the amount of AmeriCorp money they receive.

“These programs are providing services in an incredibly cost-effective way,” said Emily Haber, chief executive officer for the Massachusetts Service Alliance, a nonprofit group that oversees the distribution of AmeriCorps funding in Massachusetts.

The United Way of Massachusetts Bay and the Merrimack Valley worries about the future of its North Shore AmeriCorps program, which dispatches 25 volunteers to work with 500 students in schools in Lynn and Salem. The program aims to boost the graduation rates of students who lack fluency in English.

Although the program is less than two years old, the United Way says that 60 percent of participants already have shown increased performance in core academic classes.

“We would work to sustain it, but it would be more of a challenge to support it with only private philanthropic dollars,” said Josh Waxman, senior director of community partnerships for the United Way. “Our philosophy is we can do more together than alone.”

In Boston, the AmeriCorps cuts would exacerbate years of tight finances that have caused schools to cut cherished programs.

“These cuts would have a tremendous negative impact on our schools and on the ability of the district to connect thousands of students to mentors,” said Marsha Inniss-Mitchell, director of post-secondary partnerships and initiatives for the Boston school system.