In a frank admission of his failure to gain much voter support, New Jersey Sen. Cory Booker suggested Saturday that he might quit the race for the Democratic presidential nomination if he falls short of his fundraising goal for September.

If he can’t reach $1.7 million in donations by the end of the month, Booker wrote on Twitter, “we don’t see a legitimate long-term path forward.”

“We’re at a crossroads in this campaign,” he said.

Booker has been campaigning for nearly nine months, but less than 3 percent of Democratic primary voters support him for president, according to a RealClearPolitics aggregate of national polls.

In the early-voting states of Iowa and New Hampshire, Booker is performing slightly worse, roughly on par with Rep. Tulsi Gabbard of Hawaii and New York businessman Andrew Yang.

In an unusually blunt memo posted online Saturday morning, Booker campaign manager Addisu Demissie said Booker “might not be in this race for much longer.”

“It’s now or never: The next 10 days will determine whether Cory Booker can stay in this race and compete to win the nomination,” Demissie wrote.

On a call with reporters, Demissie said Booker had enough money to stay in the race, but needed more to be able to scale up the campaign and remain viable in the final months before voting begins Feb. 3 with the Iowa caucuses.

“Without money, we cannot build, and without building we cannot win,” he said. “We’re just saying that out loud.”

Millions of Democratic voters have had a chance to take Booker’s measure in the first three presidential debates, and he has qualified to participate in the fourth in October. The party is expected to toughen the eligibility criteria for the next debate in November.

With polls showing many Democrats undecided, it’s possible that Booker could benefit from a surge in popularity in the campaign’s final weeks. Party nominees sometimes burst into the lead late in the process, as Democrat John F. Kerry did in 2004 and Republican John McCain in 2008.

The contours of the Democratic race have sharpened in recent months, with former Vice President Joe Biden holding steady as the front-runner, followed by Sens. Elizabeth Warren of Massachusetts and Bernie Sanders of Vermont.

Sen. Kamala Harris of California, whose standing in the polls has been volatile, and Mayor Pete Buttigieg of South Bend, Ind., have emerged as a middle tier, leaving Booker and more than a dozen others struggling for a breakthrough.