In a stunning moment today, Joe Biden used his second U.S.-Mexico border visit as president to urge Donald Trump to work with him on passing the toughest immigration law in decades.

Why it matters: Biden campaigned on ending Trump-era border policies. Now he's accusing Republicans of standing in the way of his efforts to halt a historic migrant crisis.

• "Instead of telling members of Congress to block this legislation, join me," Biden said in Brownsville, Texas.
• Biden prodded House Republicans to "show a little spine" and take up the Senate border deal they helped torpedo earlier this year.

300 miles upstream in Eagle Pass, Texas, Trump said Biden has "the blood of countless innocent victims" on his hands, Axios' Shauneen Miranda and April Rubin reported.

• "The United States is being overrun by the 'Biden migrant crime,'" Trump said today.
• Immigrants are less likely to commit crimes than other U.S. residents, multiple studies have found.

The big picture: Biden's visit underscores a shift in his campaign to more forcefully address illegal immigration.

• Trump now promises mass deportations if he wins the White House again in November, after launching his presidential campaign in 2015 by casting undocumented immigrants as criminals.