Cory Booker’s presidential campaign hit another road bump on Tuesday when the New Jersey senator failed to qualify for the ballot in Vermont.

Vermont requires candidates to gather 1,000 signatures to appear on the ballot — a relatively low threshold. In addition to Booker, Senator Michael Bennet of Colorado and former Congressman John Delaney of Maryland did not reach the threshold. Former HUD Secretary Julian Castro did not initially qualify, but was granted an extension.

The Booker campaign still has a robust ballot-access program in other states. However, Vermont presents unique political challenges. Candidates need to receive at least 15% of the vote in the state to receive delegates to the Democratic National Convention in Milwaukee.

Julie McClain Downey, a spokeswoman for the Booker campaign, told Jewish Insider, “We are focused on using our campaign’s resources in the most efficient and effective way possible to win the Democratic primary and go on to defeat Donald Trump. In this case, given Vermont’s 15% threshold requirement to receive delegates, we have decided to direct our efforts elsewhere to best achieve our goals and objectives.”

In 2016, Senator Bernie Sanders swept his home state with 86.1% of the vote and won all 16 of Vermont’s delegates. His popularity in the Green Mountain State has not diminished.In the Republican presidential primary, former Congressman Joe Walsh of Illinois also failed to qualify for the ballot.