Julian Castro, former U.S. Department of Housing and Urban Development (HUD) Secretary and San Antonio Mayor, announces his candidacy for president in 2020 at Plaza Guadalupe on January 12, 2019 in San Antonio, Texas. Edward A. Ornelas | Getty Images

Julian Castro isn't one of the bigger names in the prospective Democratic field for president in 2020. But he is looking to break through with a message that stresses his experience managing large bureaucracies and budgets, as well as liberal policy proposals. Castro was one of the first Democrats to join the race to determine whom the party will nominate to challenge President Donald Trump. Castro, for his part, has been a critic of several Trump policies, notably the president's hard-line approach to immigration. Castro's campaign is pegged heavily to his experience in government. He served as mayor of San Antonio, Texas, for five years before being appointed to the top spot at the Department of Housing and Urban Development during former President Barack Obama's second term. Castro also hails from a family deeply involved in politics. His mother, Rosie, was a prominent activist, and his twin brother, Joaquin, is a congressman representing San Antonio. Here is where Julian Castro stands on key issues.

Economy and housing

Castro supports a higher minimum wage, although he has not gone as far as potential candidate Sen. Bernie Sanders and others who have been vocal advocates of a $15 hourly minimum wage. The federal minimum wage has remained at $7.25 an hour since 2009. As HUD secretary, Castro put into practice the Affirmatively Furthering Fair Housing Rule, part of the 1968 Fair Housing Act that requires cities that receive federal money for housing to examine any potential barriers or biases in housing opportunities. In 2016, the department launched the National Housing Trust Fund, which provided $173 million in grants to create affordable housing. Castro also led HUD in reducing annual mortgage insurance premiums in 2017 by about a quarter of a percent, saving homeowners $500 on average each year. Castro also spearheaded HUD's ConnectHome initiative, which provided internet access and connected devices to residents of HUD-assisted housing in 28 cities. As San Antonio's mayor, Castro launched an initiative to revitalize San Antonio's city center called "Decade of Downtown." The initiative led to $350 million of private-sector investment in housing alone. However, detractors said the plan could cause the government to neglect other areas of the city. On the campaign trail, Castro has tried to put liberal economic ideas into action. He, like a growing number of Democrats, said that his campaign will not accept donations from corporate PACs. Castro also pledged to pay his interns $15 an hour and support a campaign staff union.

Criticism over Wall Street treatment

Castro's critics said he was not tough enough on Wall Street during his tenure as HUD secretary. They point to a program at the department that sold mortgages nearing foreclosure to banks at low prices. The post-housing-crisis program, known as the Distressed Asset Stabilization Program (DASP), began in 2012 with the goal of preventing foreclosures. "Selling off our neighborhoods to Wall Street — at a steep discount — does not help keep people in their homes," several advocacy groups wrote in a petition against the program. Democratic senators, including potential 2020 candidate Sherrod Brown of Ohio, also sent a letter to HUD inquiring about the ethics of the program. HUD made a series of changes to the program in 2016 as a result of the backlash, including giving more nonprofit groups, instead of banks, opportunities to purchase the mortgages. "The DASP program was created in 2012. After joining the Cabinet in 2014, Secretary Castro directed several changes to the DASP program over two years that steadily improved the program and allowed 10,000 families to remain in their homes and even more to avoid foreclosure," Jennifer Fiore, spokeswoman for Castro's campaign, told CNBC in an email.

Immigration

Castro, the grandson of Mexican immigrants, wants to end the Trump administration's family detention policy. Earlier this year, it was revealed that thousands more migrant children were separated at the U.S.-Mexico border than previously reported. "If the President wants our immigration system to be 'the envy of the world,' he should stop putting children in cages first," Castro said in a tweet last month. In an interview with CBS' "Face the Nation," he suggested ankle monitors as an alternative to detentions and deportations, so that immigrants awaiting trial could live freely in the United States. As mayor, Castro testified during a House Judiciary Committee hearing on immigration reform in 2013, arguing that Congress should pass reforms that include a path to citizenship for undocumented immigrants.

Climate change

Castro said during his presidential announcement speech that his "first executive order" would be to return the U.S. to membership in the Paris climate agreement, which Trump withdrew from in 2017. He also endorsed a Green New Deal, which has been popularized by freshman Rep. Alexandria Ocasio-Cortez, D-N.Y. As mayor, Castro pushed city-owned CPS Energy to commit to a target of 20 percent solar energy by 2020 and to close down one of its coal-fired power plants. He also declared September "Climate Change Awareness Month" in the city. In his campaign announcement speech, Castro said the government should "say no to subsidizing big oil." Still, Castro has not gone as far on the campaign trail as fellow 2020 candidate Elizabeth Warren, who pledged not to accept donations from the oil, gas and coal industries.

Health care and education