Rep. Joe Kennedy (D-MA) is set to challenge Sen. Ed Markey (D-MA) for his Senate seat in 2020, kicking off a high profile primary battle likely to reverberate across the country.

Kennedy, a scion of one of America’s most storied political families, will formally announce his candidacy this weekend, but officially informed of his intentions during a private meeting on Wednesday.

The 38-year-old congressman has been laying the ground work for such a move since July when he quietly began commissioning polls on the feasibility of a challenge to Markey. Rumors of a campaign appeared confirmed last month when Kennedy began hiring staff and filed paperwork with the Federal Election Commission to begin raising money for a potential Senate bid.

“I don’t think primaries are something that people should shy away from,” Kennedy told reporters at the Massachusetts Democratic convention last week, according to the Associated Press.

Markey, who was first elected to the Senate in a 2013 special election to replace former Secretary of State John Kerry, has shown no intention of taking the threat lightly. Since Kennedy first signaled he was contemplating a challenge, the senator revamped his campaign by bringing on a former chairman of the Massachusetts Democrat Party to run his day-to-day operations and has hired a top Washington, D.C. pollster.

Markey has also worked to line up state and national Democrats behind his bid, most notably securing the endorsement of his congressional seat mate, Sen. Elizabeth Warren (D-MA). Some of the Democrats endorsing Markey, though, including Warren, have refused to criticize Kennedy for challenging their preferred candidate.

A matchup between Kennedy and Markey is likely to elicit national attention as both men have cultivated larger profiles in recent years. Kennedy, due to his family name and charisma, has been considered a rising star among Democrats for some time, but his path to higher office has not always been clear in deep-blue Massachusetts.

Complicating matters for the congressman is that he has not always shone when put into the spotlight, as exhibited when his response to President Donald Trump’s 2018 State of the Union was largely overshadowed by what appeared to be a drooling problem.

Markey, on the other hand, has sought to distinguish himself by championing radical proposal to tackle climate change. Alongside freshman-Rep. Alexandria Ocasio-Cortez (D-NY), Markey was the primary author of the Green New Deal earlier this year. The 73-year-old senator, known as affable but stodgy, has also carved out a niche for himself by attacking the Trump administration over its energy policies through his position as ranking member of the Senate’s Environment and Public Works Subcommittee on Oversight.

Those efforts seemed to have paid off as a number of the nation’s top environmental groups have endorsed Markey’s reelection.

It is unclear, however, if Markey will be able to adequately campaign on his environmental record given he has taken thousands of dollars from oil and gas interests since promising to spur “their dirty money.” As Breitbart News reported in July, Markey’s campaign has continued to accept money from oil and gas lobbyists even after the senator signed the No Fossil Fuel Money Pledge in December 2018. An analysis of the senator’s FEC filings indicated he has accepted thousands from individuals tied to petroleum giants like BP and Chevron.

Despite institutional support and a record as one of the most liberal members of Congress, polling has shown Markey the underdog in any matchup against Kennedy. A survey released by Commonwealth magazine in August found the senator trailing Kennedy by as 17 percentage points — 25 percent to 42 percent respectively. More troubling for Markey, the poll also found him narrowly losing a general election match up against incumbent Republican Gov. Charlie Baker, an unlikely but potential Senate candidate. Meanwhile, the poll found Kennedy beating Bakery by roughly 9 points, a still close but more comfortable margin.

On Wednesday, Markey made no mention of such polls when responding to news of Kennedy’s candidacy.

“Elections are about choices, and Ed looks forward to spending the next 14 months campaigning hard every day to show the people of the Commonwealth why he’s the right choice,” the senator’s campaign said in a statement obtained by Politico.