United States President Donald Trump became the first U.S. president to attend the yearly "March for Life" demonstration on the National Mall in Washington, D. C.

The March for Life movement started in the 1970s to oppose the legalization of abortion operations, which end pregnancies.

As thousands of movement supporters looked on, Trump told the crowd: "Unborn children have never had a stronger defender in the White House." He added, "I am proud to stand with you."

Following his short speech, some activists chanted "four more years."

Trump's speech took place at a difficult time for his presidency. Democratic representatives from the House are making their final statements for removing him from office in the nearby Senate Building.

Trump has become a strong supporter of the movement against abortion although he supported abortion rights years before seeking office.

During his 2016 campaign for president, he promised to appoint Supreme Court Justices who would support a change to the court's decision legalizing abortion. Since his election, he has appointed two conservative justices to the court, Neil Gorsuch and Brett Kavanaugh. Conservatives have a 5-4 majority on the court.

The March for Life began in 1973 after the U.S. Supreme Court established a woman's constitutional right to an abortion in its Roe versus Wade decision.

Abortion remains one of the most disputed issues in the United States. Many abortion opponents say their religious beliefs cause them to protest it as an immoral act. Abortion supporters say the medical operation is protected by the constitution. They say abortions give women control over their bodies and futures.

Other sympathetic U.S. presidents have not attended the march. Republicans Ronald Reagan and George W. Bush both sent recorded messages from other places. Trump did the same in 2017 and also sent video messages in 2018 and 2019. Vice-President Mike Pence has attended all three marches since he took office. However, he missed this year's event because of a meeting with Pope Francis in Rome.

In June, the Supreme Court is expected to rule on a case that could limit doctors' ability to provide abortions in the southern state of Louisiana. The case will test if the high court will accept laws limiting abortion that are supported by Republicans. Similar laws have been approved by legislatures in several states.

I'm Susan Shand.

The Associated Press reported this story. Susan Shand adapted it for VOA Learning English. Mario Ritter, Jr. was the editor.