In a stark reversal of his campaign messaging, President Biden vowed to tell voters "every day between now and November" that former President Trump and his GOP allies in Congress are the "only reason the border is not secure."

Why it matters: In blaming former President Trump for blowing up the Senate's bipartisan border security bill, Biden is trying to turn a policy setback into a political asset.

• "This bill won't even move forward to the Senate floor. Why? A simple reason: Donald Trump," Biden said in remarks from the White House on Tuesday. "He'd rather weaponize this issue than actually solve it."
• "The American people are going to know why it failed," Biden pledged. "I'll be taking this issue to the country."

The big picture: Biden's goal is simple, but his challenge is immense. He has nine months to pull it off.

• With his full-throated endorsement of a Senate bill that Republicans have effectively killed, Biden is guaranteeing that illegal immigration will take center stage in the 2024 election.
• That's political terrain Trump has long favored. He rode his signature "Build the wall" slogan to the White House in 2016.

Zoom in: The task for Biden is to use the trappings of the presidency to convince an angry electorate that he's more serious about fixing the border than Trump is.

• Biden is armed with soundbites from Trump's fellow GOP presidential candidate Nikki Haley and congressional Republicans that Trump would rather keep the border as a political issue than give Biden a policy win.
• "I cannot vote for this bill. Americans will turn to the upcoming election to end the border crisis," Sen. John Barrasso (R-Wyo.), the No. 3 Senate Republican, said in a statement Tuesday.

Zoom out: Congressional Republicans — not to mention Trump — have made the chaotic scenes at the southern border Exhibit A in their indictment of Biden as president.

• Trump hasn't made any effort to hide his political calculus the Senate legislation, which also included funding for Ukraine and Israel, would hurt Republicans at the ballot box.
• "This is a gift to the Democrats. And this sort of is a shifting of the worst border in history onto the shoulders of Republicans," Trump said on the "The Dan Bongino Show."
• While the White House isn't prepared to publicly declare the Senate deal is dead, Senate Minority Leader Mitch McConnell (R-Ky.), one of its key backers, appeared to accept defeat Tuesday.
• "Most of our members feel that we're not going to be able to make a law here," McConnell acknowledged.

What we're watching: Biden is walking a fine line on an issue that is dividing his own party, with some Democrats concerned Biden is channeling Trump, not challenging him.

• Latino leaders, including two prominent Democratic senators, have been railing against the bill, insisting that its restrictions on asylum were inhumane and too harsh.
• "The deal includes a new version of a failed Trump-era immigration policy that will cause more chaos at the border, not less," Sen. Alex Padilla (D-Calif.) said in a statement opposing the bill.

Between the lines: The White House's preferred outcome on the border talks was always a legislative solution, which officials hoped would unlock funding for Ukraine opposed by some Trump-aligned Republicans.

• The deal would have given Biden another bipartisan accomplishment, adding to his legislative achievements on infrastructure and semiconductors.
• But absent a win on the border, Biden will try to seize the issue and play Trump to a draw.