Democratic Rep. Stephanie Murphy is planning to announce a campaign for the U.S. Senate in Florida against Republican Sen. Marco Rubio in early June, people familiar with the matter tell Axios.

Why it matters: Murphy is a proven fundraiser. Jumping in now would give her an early start to build her case for the Democratic nomination and potentially force Rubio and allied GOP groups to spend heavily to retain a seat in a state that’s trending Republican.

• President Trump won Florida by more than 3 percentage points in 2020, up from a narrow one-point margin in 2016. He did so, in part, by accusing Democrats of being soft on socialism.
• Murphy, who fled Communist Vietnam as a child, calls herself a “proud capitalist” and has warned Democrats about embracing socialism. She knocked off a longtime GOP House incumbent in 2016 at age 38.
• Murphy has been on a “listening tour” across the state as she explains her life journey.
• “Rep. Murphy has not made a decision on whether to run for the U.S. Senate,” said Lauren Calmet, a campaign spokesperson.

Between the lines: With Murphy working to appeal to Florida voters statewide, she may be less inclined to support President Biden’s proposed tax increases on corporations and capital gains — making House passage more difficult.

• Biden won her Orlando-area district by about 10 points in 2020, and while the lines may be redrawn this year through congressional redistricting, the general area leans Democratic.

The big picture: Eighteen months before the election, both parties are looking for candidates who can appeal to swing voters in an unknown campaign climate.

• The atmospherics for the midterm races will hang on everything from Biden’s approval ratings to the level of Donald Trump’s determination to re-litigate the 2020 presidential election.
• While the Senate is tied at 50-50, Republicans are defending more seats than Democrats, giving Democrats an opportunity to increase their majority — a rarity for the party controlling the presidency at the midterms.
• In the House, the Democrat's five-seat margin could be more difficult to maintain, especially with redistricting giving Republican-leaning states additional seats.
• An Axios chart visualizes the dynamic.

Florida will be center stage in 2022 and a petri dish of presidential ambitions.

• Republican Gov. Ron DeSantis is also up for reelection, with Democratic Rep. Charlie Crist already announcing a challenge and Rep. Val Demings mulling her own.
• While Rubio ran for president in 2016, DeSantis could make his own bid for the White House in 2024, assuming he wins reelection.
• Florida Sen. Rick Scott, chairman of the National Republican Senatorial Campaign Committee, also has hinted at presidential aspirations.

The bottom line: In 2022, Florida may be less of a battleground and more of a proving ground for Democratic strategies about how to win Trump supporters.