The Note: Democratic convention choice solidifies importance of Midwest DNC Chairman Tom Perez said Monday: "The Midwest is the 'opportunity belt.'"

The TAKE with Rick Klein

The 2020 presidential election will run through Wisconsin.

There wasn't really any doubt around that -- or any real choice for Democrats. But Democratic National Committee Chairman Tom Perez made sure that the Badger State will get plenty of attention with his choice of Milwaukee to host his party's convention next July.

The decision carries substantial symbolic value for anyone who remembers the Hillary Clinton campaign. It also reflects the consensus of party strategists gaming out 2020 electoral maps that are nearly impossible to color blue without Wisconsin in their column.

Summer humidity wasn't the only thing going against the other finalist cities. Miami Beach reflected past judgments about Florida as the ultimate battleground, while Houston spoke to Beto O'Rourke-fueled longings for Democrats to turn deep-red Texas blue.

The primary landscape is moving the Democrats leftward -- and all the way left to the West Coast, where California is basically a fifth early-voting state, in the judgment offered by Sen. Bernie Sanders' campaign on Monday.

But the middle of the country is where Democrats simply must win next year, and Perez's choice means that will be advertised at the end of the primary process, in the biggest way the party can control.

Forget talk of the "Rust Belt," Perez said in Milwaukee on Monday: "The Midwest is the 'opportunity belt.'"

The RUNDOWN with MaryAlice Parks

The shrunken federal government envisioned by this White House stands in stark contrast to the expanded government -- with a focus on social programs -- imagined by many of the Democrats running for president.

President Donald Trump's suggested budget, unveiled Monday, calls only for increased military and defense spending and then pairs that with deep cuts and a retooling of education, health care and environmental programs. The acting director of the Office and Management and Budget, Russell Vought, will be on Capitol Hill Tuesday explaining the proposed budget for fiscal year 2020 and face questions about how much the president wants to spend and on what.

Democrats, on the other hand, have largely pitched more government spending in all of those areas and looked, for example, to expand federal health care spending where the president would greatly roll back funding.

The diverging agendas between the two parties means the dollar figures in the president's budget are purely aspirational, however the policies outlined will likely guide agencies' planning and work this year. For example, the president's budget talks about shifting some funds toward charter and private schools and hiring more immigration judges.

What's more the budget will easily provide talking points geared towards the president's base about cutting bureaucracy and red tape.

The TIP with Molly Nagle

Former Vice President Joe Biden will give the keynote address to the International Association of Fire Fighters Legislative Conference, an organization he has long ties to and that will almost certainly support him if he enters the race.

"I think, call it bias or not, I think he is the Democratic candidate -- if he announces -- who can actually win," IAFF General President Harold Schaitberger told ABC News. "I have been strong -- if not a pest -- in encouraging him that America needs him a lot more than he needs the presidency."

Schaitberger has known Biden for more than 40 years and said that Biden's appeal with working-class voters in the middle of the country, a group Democrats struggled with in 2016, could help win back the White House, adding: "Joe Biden has the voice that can reach Middle America."

While Biden has not announced his plans, he's likely to feel the enthusiasm from the firefighters for a 2020 bid. Biden says he has his family's support if he decides to run, and he will be introduced by his wife, Dr. Jill Biden, at the event Tuesday in Washington.

THE PLAYLIST

ABC News' "Start Here" Podcast. Tuesday morning's episode features question surrounding Ethiopian Airlines Flight 302, as ABC News Chief National Correspondent Matt Gutman joins us from Addis Ababa. Later, ABC News Chief White House Correspondent Jonathan Karl presses the White House on the ballooning budget deficit. http://apple.co/2HPocUL

ABC News' "The Investigation" Podcast. "The Investigation" talks to David Bossie, Donald Trump's former deputy campaign manager, and Keith Davidson, the former attorney for adult-film star Stormy Daniels and Playboy Playmate Karen McDougal -- two women who received hush money payments after allegedly having affairs with Trump. https://apple.co/2GjL25N

FiveThirtyEight's Politics Podcast. Democrats have been out of the wilderness and in control of the House of Representatives for a little over two months, and with that newfound power has come a greater focus on the divisions within the party. In this episode of the FiveThirtyEight Politics podcast, the crew looks at where the party's fault lines are, and what those divisions could mean for the party going forward. The gang also dives into why some potential candidates, like Sen. Sherrod Brown of Ohio, decided not to run in 2020. https://apple.co/2mKrhcF

WHAT YOU NEED TO KNOW TODAY

The president will be presented with the Boy Scouts' Report to the Nation at 11:45 a.m. in the Oval Office. At 1:45 p.m., he participates in a signing ceremony of "The John D. Dingell, Jr. Conservation, Management, and Recreation Act."

Former Vice President Joe Biden speaks at the International Association of Fire Fighters' Conference at 9 a.m. in Washington.

The House Budget Committee holds a hearing on the president's 2020 budget at 10 a.m. on Capitol Hill.

Speaker of the House Nancy Pelosi, Rep. Lucille Roybal-Allard, D-Calif., and House Democrats introduce "The Dream and Promise Act" to protect Dreamers and TPS recipients at 10 a.m. on Capitol Hill.

The House Energy and Commerce Committee convenes to discuss the 2020 Health and Human Services budget with HHS Secretary Alex Azar at noon on Capitol Hill.

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The Note is a daily ABC News feature that highlights the key political moments of the day ahead. Please check back tomorrow for the latest.