President Trump brought his 2016 presidential rival Hillary Clinton back into his 2020 re-election campaign during his speech on Tuesday, prompting "lock her up" chants from the crowd.

Why it matters: Trump seemed more focused on Clinton at his official campaign launch than he was on any of the 2020 Democratic candidates. He promised supporters he would find Clinton's deleted emails from her time as secretary of state. He had previously claimed he was joking about requesting the emails from Russia, though the Mueller investigation found Trump repeatedly asked Michael Flynn to get them in 2016.

The big picture: Early in his speech, Trump made Clinton a focal point, blaming her for the 3 years of investigations into alleged collusion with Russia. He claimed the probes were nothing more than an "insurance policy" Democrats used to undo his 2016 win. He fired up supporters by saying Democrats tried to suppress their votes.

"They appointed 18 very angry Democrats to try to take down our incredible movement... 1.8 million pages of documents. 500 search warrants. 500 witnesses. 2,800 subpoenas and 40 FBI agents working around the clock. What did they come up with? No collusion. No obstruction."

— Trump during this first 2020 campaign rally

Trump claimed former President Obama "did nothing" when his predecessor was first informed about possible Russian interference during the elections because he believed Clinton was going to win.

What to watch: Trump's other 2020 enemy seems to be the concept of socialism, which is gaining popularity in the U.S. He claimed "America will never be a socialist country" because Republicans "believe in freedom." Vice President Mike Pence made similar comments at the rally.

On unity, Trump said he's ready to work with Democrats, but they simply don't want to. He called for "one American team". ( Reality check: Trump said in May he wouldn't negotiate with Democrats in Congress until they call off their investigations. The White House has asserted executive privilege in an effort block current and former Trump officials from complying with subpoenas from House Democrats.)

Trump said he's ready to work with Democrats, but they simply don't want to. He called for "one American team". ( Trump said in May he wouldn't negotiate with Democrats in Congress until they call off their investigations. The White House has asserted executive privilege in an effort block current and former Trump officials from complying with subpoenas from House Democrats.) On his record as president, he touted economic successes and job rises nationally.

he touted economic successes and job rises nationally. On health care, Trump promised to eradicate AIDS from the U.S. as well as find a cure for cancer, but he didn't explain how. He pledged to protect patients with pre-existing conditions. He didn't elaborate as to how, though he's said there'd be no replacement for the Affordable Care Act until after the 2020 elections.

Trump promised to eradicate AIDS from the U.S. as well as find a cure for cancer, but he didn't explain how. He pledged to protect patients with pre-existing conditions. He didn't elaborate as to how, though he's said there'd be no replacement for the Affordable Care Act until after the 2020 elections. On immigration, he claimed schoolchildren are being threatened across the country by the gang MS-13, and that his administration is working to deport them by the thousands. Meanwhile, Democrats are advocating for open borders, according to Trump. ( Reality check: MS-13 is a violent gang with about 10,000 members, mostly from Central America. Most immigrants crossing the border are not interested in joining them, and most Democrats are not advocating for open borders.)

he claimed schoolchildren are being threatened across the country by the gang MS-13, and that his administration is working to deport them by the thousands. Meanwhile, Democrats are advocating for open borders, according to Trump. ( MS-13 is a violent gang with about 10,000 members, mostly from Central America. Most immigrants crossing the border are not interested in joining them, and most Democrats are not advocating for open borders.) On environment, Trump claims the U.S. has the cleanest water and air in the world.(Reality check: Water pollution and air quality has worsened under Trump.)

Trump also declared a new campaign slogan: "Keep America Great."