MIAMI – The ad sounds like something out of the GOP 2024 playbook, trumpeting a senator's work with Republicans to crack down on the flow of fentanyl and other illegal drugs into the U.S., getting tough on Chinese interests helping smugglers, and noting how he “wrote a bill signed by Donald Trump to increase funding for Border Patrol.”

It's actually a commercial for Sen. Sherrod Brown, an Ohio Democrat facing a tough reelection fight that will help decide control of the Senate.

“Ohioans trust Sherrod Brown to keep us safe,” says the narrator of the ad, sponsored by the Democrat-aligned Duty and Country PAC. His campaign declined to comment.

The message is one more indication of the political and security challenges the U.S.-Mexico border has presented for President Joe Biden. Some Democrats across the country are distancing themselves from the White House, and polls indicate widespread frustration with Biden's handling of immigration and the border, creating a major liability for the president's reelection next year.

The Biden administration this week took two actions seen by many as moving to the right on immigration.

The Department of Homeland Security waived environmental and other reviews to construct new portions of a border wall in South Texas after Biden pledged during the 2020 campaign that he would build “not another foot” of wall. And U.S. officials said they would resume deportations to Venezuela not long after the administration increased protected status for thousands of people from the country.

Both moves inflamed conservatives and liberals alike. Many Republicans accused Biden of being too late to adopt former President Donald Trump's ideas on a border wall, while liberals who oppose additional border restrictions accused the White House of betraying campaign pledges.

“My frustration has been that we are not addressing immigration in a holistic way as a country. We are depending on the president alone,” said Rep. Veronica Escobar of Texas, a Democrat who represents the border city of El Paso and is a national co-chair of the Biden reelection campaign. “We are treating people from different nationalities in a different way. And the pathways that have been created are being challenged in court consistently.”

Biden has said his administration moved forward with the border wall because it was required by Congress during the Trump administration, even though he considers it ineffective. His reelection campaign pointed to Trump's record at the border, including his administration's practice of separating immigrant families as a deterrence measure and the temporary detention of children in warehouses in chain-link cells.

“MAGA Republicans are running on the legacy of Donald Trump's playbook of family separation, caging kids, and shouting 'border!' without any serious solutions,” said Kevin Munoz, a spokesman for Biden's reelection campaign, referring to supporters of Trump's “Make America Great Again” movement.

Border crossings hit two-decade highs under Trump but fell during the first months of the COVID-19 pandemic, with immigration authorities expelling most border crossers using public health authority known as Title 42.

Upon taking office, Biden paused border wall construction and canceled the Trump administration's “Remain in Mexico” program, but kept expelling many people under Title 42 until this past May.

Still, border crossings are now skyrocketing, which some observers blame on his administration for creating the perception that the border was open. The White House counters that migration has surged across the Western Hemisphere due to regional challenges out of the administration's control.

Conservative media outlets often spotlight border crossings and blame Biden for creating what they say is a crisis. But Biden has taken criticism from many in his own party, including Democratic mayors and governors who want more help caring for newly arriving migrants.

Republican-led border states started busing thousands of immigrants to Democratic-led cities across the country, creating in many places a huge shortage of space that's led to makeshift shelters and camps.

A Marquette Law School poll of registered voters conducted in late September gave Trump, the front-runner for the 2024 GOP nomination, a 24-point advantage over Biden on handling immigration and border security issues – 52% to 28%.

The Republican focus on immigration and the border didn't stop Democrats from big victories in the 2018 midterms and Biden and Democrats beat expectations during last year's election as well, keeping the Senate and losing the House by a tiny margin to Republicans. But there were some troubling signs even then.

About six in 10 voters then said they disapproved of how Biden was handling the issue of border security, according to AP VoteCast, a sweeping national survey of the electorate. Some 27% of Democrats disapproved of how Biden was handling the border, with one-third of Democrats who identify as moderate or conservative saying this was an issue where they disapproved of Biden's performance, according to VoteCast.

Border security was also a weak spot for Biden among independents, with 66% saying they disapproved.

Sixty-one percent of Democrats said they wanted stronger law enforcement at the border, as did two-thirds of Latino or Hispanic voters (65%).

Escobar, who is a leading Hispanic voice for the Biden campaign, said she is concerned that immigration could hurt the president's reelection efforts.

“There is going to be a tendency to blame the White House when in fact this has been a failure on Congress,” she said. The last major immigration reform approved by Congress was in 1990.

Weissert reported from Washington. Associated Press writer Linley Sanders in Washington contributed to this report.