Scoop: Sinema's secret spreadsheets

Sen. Kyrsten Sinema (D-Ariz.) is negotiating the size and scope of President Biden’s $3.5 trillion budget plan armed with her own spreadsheets about the costs and tax hikes needed for each program, people familiar with the matter tell Axios.

Why it matters: While Sen. Joe Manchin (D-W.Va.) is getting attention for balking at a $3.5 trillion top-line price tag, Sinema's accountant-like focus on the bottom line will be equally important to winning the votes of them and other key Democrats.

• Sinema’s intense interest in the numbers also suggests she’ll be a formidable foil for progressives — like Sen. Bernie Sanders (I-Vt.) — who are working to make the spending bill as big as possible.
• “As she has said publicly, Sen. Sinema will continue working in good faith with her colleagues and President Biden as this legislation develops — and will be closely reviewing what the committees propose," said John LaBombard, Sinema’s communications director.

The big picture: Despite the focus on Manchin, party leaders and the White House are aware of Sinema's potential concerns.

• As early as July, she was clear the $3.5 trillion price tag was too high for her.
• The lack of clarity about how long each program will last has frustrated both senators and outside budget groups.
• The Committee for a Responsible Federal Budget has tried to bring uniformity to the process and ended up pricing the reconciliation package at $5.5 trillion.

Between the lines: Sinema and Manchin aren’t necessarily on the same page on which programs — and which tax increases — they can stomach.

• Crafting a deal to address Manchin’s concerns doesn’t ensure Sinema also will be happy.

Behind the scenes: Sinema refers to her spreadsheets as she strategizes with colleagues about next steps in the budget process.

• As House and Senate committees begin to write specific legislation, she’s updating her data to ensure she has accurate top- and bottom-line figures.

The bottom line: By internalizing the numbers, Sinema is prepared to challenge parts of Biden's overall $3.5 trillion package.

• She’s also putting herself in a position to cut deals, as she did when she helped broker the $1.2 trillion bipartisan infrastructure package.
• It received 69 votes, including 19 Republicans, in the Senate last month.