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President Trump started comparing crowd sizes even before he took the stage at the El Paso County Coliseum on Monday night. "We have a line that is very long already," Trump said at the White House earlier Tuesday. "And I understand our competition's got a line, too, but it's a tiny, little line." The "competition" would be an anti-wall march organized by more than 40 local civic and human rights groups, headlined by El Paso native and potential 2020 candidate Beto O'Rourke.

About 30 minutes into his rally, Trump said he had been challenged by "a young man who's got very little going for himself except he's got a great first name. ... So we have, let's say, 35,000 people tonight, he has 200 people, 300 people — not too good," Trump claimed. "That may be the end of his presidential bid." He said later that 10,000 people were inside the stadium. Donald Trump Jr. also tried to mock Beto's crowd size.

Trump's audience inside the coliseum was 6,500, at capacity, El Paso Fire Department public information officer Enrique Aguilar told the El Paso Times. "It might be 10,000 with the people outside," watching on monitors. The rally O'Rourke spoke at, following a mile-long march, drew at least 7,000 people, The Texas Tribune reports. Bloomberg's Jennifer Epstein says that's an undercount:

The substantive disagreement between O'Rourke and Trump was about the efficacy and wisdom of border walls, and a vision for America. "Walls work," Trump said. "Walls save lives." He claimed, incorrectly, that El Paso became safer after border fencing was erected in 2009, saying "they're full of crap when they claim it hasn't made a big difference." O'Rourke called El Paso "one of the safest cities in America," and it's "safe not because of walls but in spite of walls." You can watch Beto's speech below. Peter Weber