As the nation prepares to inaugurate Donald Trump this week, college presidents will face the challenge - perhaps greater than ever before - of advocating for issues important to their campuses, while still respecting a presidential administration that may be on the opposite side.

Already, dozens of local presidents have signed on to letters to Trump, expressing support for undocumented college students, asking for action on climate change, and urging him to take a more forceful stand against incidents of racism and bigotry following his election.

They have had to deal with demonstrations on their campuses and students worried they will be targeted for deportation or discrimination in a Trump presidency.

At the same time, they must tread carefully so as not to anger a new federal administration that will influence higher-education policy.

"They are walking a very thin line between advocacy on behalf of a whole range of issues that at least appear threatened and at the same time showing due regard and respect to the office of the president and attempting not to alienate an incoming administration," said Barmak Nassirian, director of federal relations and policy analysis for the American Association of State Colleges and Universities.

Alison Byerly, president of Lafayette College in Easton, said the issues were too important not to take a stand. She signed all three letters, on undocumented students, climate change, and racism.

"I see these letters as not being about political positions but being about values," Byerly said.

Presidents who originated the letters to Trump said they felt compelled to speak out as a group with hope that their carefully worded statements would carry more weight.

"In moments that are inflection points, it is important to take a stand," said Mariko Silver, president of Bennington College in Vermont. "College and university presidents may not always feel like they are people in positions of power, but in fact we are powerful voices, and we felt it was time to use our voices."

Silver started the letter asking Trump to condemn racism and hate. It was signed by nearly 200 college presidents, including more than a dozen Philadelphia-area leaders.

"In light of your pledge to be 'President for all Americans,' we urge you to condemn and work to prevent the harassment, hate and acts of violence that are being perpetrated across our nation, sometimes in your name, which is now synonymous with our nation's highest office," the letter said.

Some presidents, including Julie E. Wollman of Widener University in Chester, did not sign the letters, preferring to wait and see what the Trump administration does.

"One of the things we learned from the results of the election is that there are a lot of people in this country who feel like they haven't been heard or listened to," she said. "We are a divided country. . . . We need to find the common spaces in those divisions."

She sees her role as fostering inclusiveness on campus, allowing for different views to be expressed and respected.

"Our graduates are going to be working in a diverse world with people who have different perspectives," she said.

Given the liberal lean of many campuses compared with the new administration, "I think we will have many flash points," said Richard Ekman, president of the Council of Independent Colleges, an association of 680 schools. But, he said, it's hard to know whether being a college president will be harder, because so little is known about Trump's higher-ed agenda.

Some college presidents declined to discuss how they see their role, perhaps pointing to the sensitivity of the topic. Temple University president Richard Englert would only issue a statement.

"As a state-related institution, we are eager to collaborate and work closely with elected leaders at all levels and of all political persuasions to ensure that Temple remains a national model for accessible, affordable, diverse, high-quality education and research," Englert said.

Englert was one of 550 college presidents who signed a letter asking that Trump not disturb a policy put in place by President Obama allowing undocumented college students to continue their studies without fear of deportation. Trump initially said he was in favor of rolling back Deferred Action for Childhood Arrivals (DACA) but has since indicated he was interested in working something out.

Other presidents were willing to talk - and said it's important to do so.

"College and university presidents have to address it, but they have to do it in a manner that promotes the free exchange of ideas, in a manner that does not exclude voices," said Harvey Kesselman, president of Stockton University, who signed the letters on undocumented students and climate change. "So it should be done in a way that's inclusive, and it should be done in a civil way, and that's not always the easiest thing to do. It's complex to know when to enter it and when to stay back and watch it unfold."

Eric Barron, president of Pennsylvania State University, said he doesn't see his role as changing.

"I consider myself to be very apolitical," Barron said. "I believe I have one thing to focus on, and that's the success of public higher education. What I say is not going to change. How I say it is not going to change. That consistency of message is very important regardless of who is in office."

Barron signed the letter regarding undocumented students.

"I believe strongly if someone is educated in one of our high schools and does well, our job is to accept those students and help them excel," he said.

Byerly, of Lafayette, was one of more than 120 presidents who asked Trump to "take aggressive climate action; to reduce our sector's carbon pollution, to support interdisciplinary climate education, and to continue research that expands our understanding of rapidly changing earth systems."

"Climate change has been cast as a political position," Byerly said, "but it's really a scientific reality that the country needs to come to grips with."

She expects that the letters may be only the beginning of an increased role for college presidents to speak on national issues that affect their campuses.

R. Barbara Gitenstein, president of the College of New Jersey, who signed the climate letter, agrees.

"It's recapturing what should have been our responsibility all along," she said. "I'm of the generation that participated in a lot of conversation on campuses, and I find that very healthy."