Former Virginia senator Jim Webb will not run for president as an independent, he announced Thursday during a speech in Dallas.

Webb dropped out of the Democratic primary in October, having failed to gain traction in early polling and debates. Since then he has been exploring the possibility of launching an independent bid, going so far as to hire a fundraising director. But running as an independent presents immense financial and logistical challenges.

“We looked at the possibility of an independent candidacy. Theoretically it could be done, but it is enormously costly and time sensitive, and I don’t see the fundraising trajectory where we could make a realistic run,” Webb said during a speech to the World Affairs Council of Dallas/Fort Worth, according to his campaign.

The former senator and Vietnam veteran is continuing to criticize candidates in both parties for what he sees as a lack of serious engagement with foreign policy. Webb, who served as the secretary of the Navy under President Ronald Reagan, used his campaign to criticize the Obama administration’s military intervention in Libya, its nuclear negotiations with Iran and its handling of the relationship with China.

“We have not had a clear statement of national security policy since the end of the Cold War, “ Webb said Thursday. “And I see no one running for president today who has a firm understanding of the elements necessary to build a national strategy.”

Michael R. Bloomberg, the billionaire former mayor of New York City, is still considering an independent bid.