Who President Trump invited to his first joint address to Congress

— -- On Tuesday night, President Donald Trump will make his first address to a joint session of Congress where he is expected to lay out his policy vision for the year ahead -- and the guests announced by the White House offer a glimpse into the possible stories he’ll use to illustrate his plans.

The guests chosen to sit with the First Lady in her House gallery viewing box are often referenced by name in a president’s speech. This year, the six guests hosted by First Lady Melania Trump include the wife of the late Supreme Court Justice Antonin Scalia, three relatives of victims of crimes that authorities say were committed by undocumented immigrants, the daughter of a healthcare start-up founder and a student and advocate for tax-credit scholarships. School choice, healthcare and immigration were key themes in an outline of Trump’s speech circulated by the White House.

But it’s not just the President and First Lady who bring guests to Capitol Hill — members of Congress also invite constituents. This year, Democratic members of Congress have invited guests including Muslim Americans, undocumented immigrants and beneficiaries of the Affordable Care Act to represent people they feel have been disadvantaged by Trump’s policies. Across the aisle, Republican members of Congress will be bringing guests that include an opioid abuse prevention advocate, the wife and brother of a police officer killed in the line of duty, and a teamster from Ohio.

Here’s who will be joining First Lady Melania as guests of the White House tonight:

Megan Crowley

When Megan Crowley was only 15 months old, her parents learned that she was diagnosed with what could be seen as a death sentence—Pompe disease. A rare genetic disorder that causes the breakdown of muscle tissue, untreated Pompe disease can lead to early childhood death. The Crowleys learned that Megan wasn’t their only child who had Pompe disease; her younger brother Patrick tested positive as well.

Their father, John Crowley, facing the agonizing prospect of losing his children, looked to find a cure. Crowley, who previously worked for pharmaceutical company Bristol-Myers Squibb, began fundraising to help find a cure and raised over $100 million dollars to start a biotech company in Oklahoma City focused on researching new treatments for the disease. The company developed a drug that greatly prolonged both Megan’s and Patrick’s lives.

Now 20 years old, Megan Crowley is a sophomore at her father’s alma mater, Notre Dame, where she said she studies with the assistance of a nurse.

Megan Crowley, escorted by her father John, will attend tonight.

Denisha Merriweather

As a child, Denisha Merriweather struggled with school and was held back twice in the third grade.

"I didn’t have hope, I dreaded going to school," Merriweather told ABC News.

When she reached the sixth grade, her godmother, Johnell Jones, enrolled her in the private school Esprit de Corps Center for Learning in Jacksonville with the help of Florida’s tax-credit scholarship program, which allows corporations to receive a tax break for donations to private schools and scholarship programs.

Merriweather went on to be the first person in her family to attend college and the first to earn a bachelor’s degree. She’s currently working on a master’s degree in social work at the University of South Florida and spends part of her time advocating for school voucher programs. Last summer, Merriweather spoke on a panel at the Republican National Convention.

"I think it’s really great that the president will show how someone actually benefited from school choice, and I’m excited to be here tonight to represent the school choice movement and show how the federal government is moving to advance options," said Merriweather.

While not a Republican, Merriweather has appeared frequently with former Florida Governor Jeb Bush and supported Trump’s pick for Secretary of Education, Betsy DeVos. On Tuesday, Merriweather appeared with DeVos at the Historically Black Colleges and Universities congressional luncheon.

Maureen McCarthy Scalia

When President Donald Trump announced his selection of Neil Gorsuch as his nominee to the Supreme Court, he singled out Maureen Scalia, the wife of the late Supreme Court justice Antonin Scalia.

"She is really the ultimate representative of the late, great Justice Antonin Scalia, whose image and genius was in my mind throughout the decision-making process," said Trump.

Maureen Scalia was married to the late justice for more than 50 years, after they met as students at Harvard University.

Out on the campaign trail, Trump said that Maureen Scalia had a Trump sign in her yard and he promised to select a new Supreme Court justice in the vein of Scalia. Her presence tonight signals that Trump will not only honor Scalia’s memory through his widow, but also reinforce his selection of Gorsuch for the Supreme Court.

Gorsuch met with Maureen Scalia after Trump’s Supreme Court announcement.

Jessica Davis and Susan Oliver

In 2014, Detective Michael Davis and Deputy Sheriff Danny Oliver were killed in the line of duty in Sacramento, California. An undocumented immigrant is accused and will stand trial for the crime. Their widows, Jessica Davis and Susan Oliver, have been mentioned by Trump out on the trail and will join the First Lady tonight for his address.

The David-Oliver bill, introduced in the Senate by Trump’s now attorney general, Jeff Sessions, is named after the two men and is aimed at increasing cooperation between federal and local officials to enforce immigration laws. It would require states to notify the federal government of undocumented immigrants with criminal records.

Jamiel Shaw, Sr.

In 2008, Jamiel Shaw, Jr., a 17-year-old high school football star, was shot and killed near his home in Los Angeles by a gang member who was living in the United States illegally.

His father, Jamiel Shaw, Sr. has appeared with Trump at campaign events and even spoke during the Republican National Convention about losing his son. Shaw has praised Trump’s positions on immigration and his hardline approach to border security.