Originally Published: 27 MAY 21 08:00 ET

Updated: 27 MAY 21 09:43 ET

By Phil Mattingly, Lauren Fox and Betsy Klein, CNN

(CNN) -- Senate Republicans made a $928 billion counteroffer to President Joe Biden's sweeping infrastructure proposal Thursday morning as one of the President's closest advisers rallies allies to embrace the White House's proposals.

The group of Senate Republicans negotiating with Biden on infrastructure unveiled their latest infrastructure counter-proposal Thursday morning, just ahead of the latest effort from the President to put the spotlight back on his sweeping economic agenda. The offer falls short of the $1 trillion that Senate Republicans had said Biden was open to during their White House negotiations.

According to a document obtained by CNN, the GOP offer includes $506 billion for roads, bridges and major projects; $98 billion for public transit systems; $46 billion for passenger and freight rail; $21 billion for safety; $22 billion for ports and waterways; $56 billion for airports; $22 billion for western water storage; $72 billion for water infrastructure; $65 billion for broadband infrastructure; and $20 billion for infrastructure financing.

The offer comes as Mike Donilon, senior adviser to Biden and one of his closest aides, told allies in an internal memo obtained by CNN that the moment is "an inflection point" for the future of both the economy and country.

Donilon sought to directly counter GOP objections to both the scale of Biden's proposal, as well as the corporate tax increases he has proposed to pay for it.

"When Republicans criticize the President's plan to rebuild our economy through long-overdue investments in our country's infrastructure, they're criticizing what their own constituents have been urging for decades," Donilon wrote in the memo circulated Thursday morning. "When they attack the President's plan to make the wealthy pay their share of taxes, they're attacking the American people's basic sense of fairness."

Biden will travel to Cleveland, Ohio to give what White House officials are calling a "major" economic speech at a critical moment in the bipartisan negotiations over a potential infrastructure deal. The speech is set to mark a symbolic return to normal as the US makes strides against the pandemic and economic recovery continues. Biden will speak on the economy at Cuyahoga Community College -- which, a White House official said, is "the site of the last rally he was scheduled to hold as a candidate in March 2020 before the pandemic shut down our country."

With that symbolic backdrop, Biden will tout his administration's economic plan, cite progress against the virus as 50% of American adults are now vaccinated, and make a push toward his sweeping infrastructure package.

After weeks of back and forth, with no clear pathway toward an agreement to this point, the Senate Republican group's counteroffer is the latest flashpoint.

Biden, whose most recent proposal was $1.7 trillion, has indicated he'd be open to discussing a $1 trillion plan, senators have told CNN. But the disputes up to this point go far beyond the overall cost, with sharply different views over the scale of any potential compromise proposal and how it would be paid for continuing to serve as major roadblocks.

Biden has made clear, both publicly and privately to advisers and allies, he sees value to striking a scaled back bipartisan deal, even if it means pushing off elements of his initial $2.3 trillion infrastructure and jobs proposal until a later effort. But he's also made clear he's not willing to sharply scale back the full scope of his proposal.

Donilon, in his memo, underscores that position on the policy and makes clear Biden will emphasize it in his remarks in Cleveland.

"He'll talk about the historic investments in roads, bridges, (research and development), manufacturing, and education that we must make to create good-paying jobs and ensure all Americans are lifted by the rising tide of prosperity," Donilon wrote. "He'll talk about what we can, and must, do to ensure that the future is made in America -- and that we can continue to out-compete and out-innovate China and the rest of the world in the 21st century."

But Donilon also used the memo to hammer home a key point White House officials have been trying to impart on allies for months: the proposals Biden has put on the table are largely supported, according to polling. Donilon cites more than a dozen polls in the memo to make that point -- one officials view as leverage in their negotiations with Republicans.

"The American people -- across the political spectrum -- are sending a clear message, the question now is whether Congressional Republicans will listen," Donilon writes.