BOSTON -- A lawsuit charging Harvard University of discriminating against Asian American applicants in admissions went to trial on Monday at a US District Court in Boston, drawing nationwide attention as the future of the affirmative action is also on the debate.

The Students for Fair Admissions (SFFA), a non-profit group that believes schools should not consider race when selecting students, sued four years ago that over decades, Harvard has rigged its highly selective undergraduate admissions system against Asian American applicants by using "de facto racial quotas, racial stereotypes and higher standards". Harvard has denied the charges.

US District Court Judge Allison Burroughs, who was nominated by then Democratic President Barack Obama and seated in 2015, is presiding over the trial.

At the packed courtroom on Monday, the plaintiffs accused that Harvard intentionally ranks Asian American applicants lower on "personal rating" scores used to measure character traits such as leadership, grit, courage and likeability, presenting a document they say is Harvard's only guidance on the personal rating loosing ranging from one for "outstanding" to five for "questionable personal traits."

In response, Harvard's legal team denied all the allegations, saying race is just one factor that's considered while only considered in a limited way, arguing a race-conscious admissions process is essential to ensuring that students are exposed to a variety of viewpoints.

In a series of decisions since 1978, the Supreme Court has allowed race-conscious admissions if carefully done, and according to Harvard, Asian Americans now account for 23 percent of all admitted students.

Outside the federal courthouse, a number of Asian American protesters showed up Monday morning when the trial went on, carrying banners with "HARVARD NO MORE RACIAL STEREOTYPING" and "Discrimination in the name of diversity is wrong".

However, Asian Americans are deeply divided on the case. On Sunday, hundreds of Asian Americans rallied in central Boston to show support for the SFFA lawsuit. About five kilometers away, dozens of Asian American Harvard students rallied at the Harvard Square to protest against the lawsuit and show support for the affirmative action, citing the benefit of the affirmative action and the importance of diversity on campus.

This is Judge Burroughs' first trial without a jury. She expects to issue a verdict after it ends in around three weeks, local media reported.

However, any verdict faces a near-certain appeal. It is widely expected the case could reach the Supreme Court.