bleed into

Hello. Could someone explain to me what the phrase "bleed into" means, please? I found the phrase in a sentence from the part of a TIME article arguing that the orderly society built up by the FDR administration was regarded stifling and suffocating by the baby-boom generation. Here’s the sentence in question: And it was this movement for racial, sexual and cultural liberation that bled into the movement against Vietnam and assembled in August 1968 in Grant Park.

Does "bled into" in this context mean something like "fueling"?

Thank you so much in advance.