U.S. Sen. Susan Collins will not attend President Donald Trump’s midterm Republican convention in Dallas next week.

The convention is slated for Sept. 9-10 — less than two months before the Nov. 3 election.

Promotional material for the event features Trump and says the program will focus on his domestic, “America First” agenda. Trump will headline the event, and other potential speakers include Vice President JD Vance, first lady Melania Trump and members of Trump’s Cabinet.

A Collins campaign spokesperson said the senator has a long-standing practice of not going to conventions when she is up for reelection.

“Senator Collins has never attended a convention during a year when she was in cycle,” spokesperson Blake Kernen said. “She runs her own campaign, independent of any national party schedule.”

Collins is seeking a sixth term in the Senate. She’s being challenged by Democrat Troy Jackson, a fifth-generation logger from Allagash and former Maine Senate president. And polling has shown a tight race.

Maine’s race is being closely watched. It’s one of a handful of national contests that could determine the balance of power in Washington, D.C.

Republicans currently control the White House and both chambers of Congress. Democrats need to flip four seats to regain control of the Senate. And Collins is the only Senate Republican running in a state won by Democrats in the 2024 presidential race, making her a prime target.

Democrats have been trying to tie Collins to Trump, who has low approval ratings nearly halfway through his second term. But Collins has tried to highlight her independence, saying she has worked with presidents of both parties when it’s to Maine’s benefit and opposed them when it’s not.

Collins has found herself the target of Trump’s criticism in the past. But the president has also acknowledged that from Republicans’ perspective, Collins needs to win reelection this cycle.

Vance has mentioned Collins’ independence at both of his appearances in Maine this year. Collins did not attend either event, but received praise from the vice president.

In Brewer last month, Vance joked that Collins “sometimes makes my job a little bit harder” because she is “the most independent member of the United States Senate.”

“But she makes it harder because she is coming in to work every day and not fighting for a political party or any abstraction,” he said. “She comes to work and fights for the people of Maine.”

Collins is not alone in skipping the midterm convention.

Politico surveyed 70 Republican candidates and found that a majority — 45 — did not plan to attend or were still deciding.