BROWNSVILLE, Texas — On the banks of the same Rio Grande but 300 miles apart, President Joe Biden and GOP challenger Donald Trump on Thursday surveyed the U.S.-Mexico border and tussled from a distance over who is to blame for the nation’s broken immigration system and how to fix it.

Immigration has emerged as a central issue in the 2024 presidential campaign, which is widely expected to be a Biden-Trump rematch, and each man is seeking to use the border problems to his own political advantage.

Their itineraries were remarkably similar: They arrived in Texas within a half-hour of one another. Each chose an optimal location from which to make his point, got a briefing on operations and issues, walked along the scrub brush by the Rio Grande and spoke directly to the public. Their remarks even overlapped in time for a bit.

But that’s where the parallels ended.

Biden sought to spotlight the necessity of a bipartisan border security bill that was tanked by Republicans on Trump’s orders, and flat-out asked the Republican front-runner to join him in supporting a congressional push for more funding and tighter restrictions.

“Here’s what I would say to Mr. Trump,” Biden said. “Instead of playing politics with the issue, join me, or I’ll join you in telling the Congress to pass this bill. You know and I know it’s the toughest, most efficient, most effective border security bill this country’s ever seen.”

Biden went to the Rio Grande Valley city of Brownsville, which for nine years was the busiest corridor for illegal crossings. The numbers have dropped in recent months, which officials credited in part to Mexico for stepping up its own border security. The visit was a nod to how the Biden administration views migration: as a regional and global issue, not just a U.S. problem.

The president walked along the Rio Grande and received a lengthy briefing from Homeland Security officials, who spoke bluntly about what they needed to do their jobs effectively — in short, more money to hire more officers along the border and for use across the asylum process to help clear out massive backlogs.

“I want the American people to know what we’re trying to get done,” Biden said. “We can’t afford not to do this.”

Trump simply blamed Biden.

He traveled to Eagle Pass, roughly 325 miles northwest of Brownsville, in the corridor that’s currently seeing the largest number of migrant crossings. He met with Republican Gov. Greg Abbott and Texas National Guard soldiers who have commandeered a local park and put up razor wire fencing at the river’s edge to keep migrants from crossing illegally. The park has become a Republican symbol of defiance against the federal government.

“This is like a war,” Trump said.

Gazing out over the river through the razor wire, Trump raised his fist and waved and shouted to people on the Mexico side, who waved back. Then, he declared that migrants arriving to the border were criminals and some were terrorists, a dialed-up version of the accusations he often used during the 2016 campaign. This time, he’s started to harness rhetoric once used by Adolf Hitler to argue migrants are poisoning the blood of America.

“They’re being let into our country and it’s horrible,” Trump said. “It’s horrible.”

Trump also brought up the killing of a 22-year-old nursing student in Georgia recently. The suspect is a Venezuelan migrant.

“Crooked Joe has the blood of countless innocent victims,” Trump said. “It’s so many stories to tell, so many horrible stories.”