authorship - Co-author contributed almost nothing and is blocking publication

Alice and Bob have co-authored a paper together. The contribution (data collection, analysis, writing) was 100% Alice and 0% Bob, except that the original idea was initiated during a conversation between Alice and Bob. Bob acknowledged several times in private that he did not contribute to the project, but he claimed co-authorship for the idea and Alice did not object to that. Alice spent almost an entire year working on the project. Bob spent less than a couple of hours in total. A manuscript with both names has already been circulated, submitted and rejected from one journal.

Bob is now trying to block the publication of the paper due to a personal conflict with Alice. In the meantime, Bob became envious of Alice's early successes and decided to do everything to slow down her career, even at the expense of his own publication record. Bob is already tenured and has no pressure to publish. Alice, by contrast, needs more publications for her forthcoming tenure review. Of course, Bob never explicitly refused to submit the paper. But instead of sending it to a prestigious outlet (where the paper would have a good shot) he insists that they send the manuscript to a non peer-reviewed and unknown journal, which would not help Alice's tenure case. Of course he makes no effort in trying to find an agreement, as he would be happy not to submit the paper at all. Clearly, his decisions are driven by spite and malevolence only and he takes great care into not writing anything incriminating for him.

Is there anything that Alice can do in that situation? Does she have to resign herself to never publishing the paper? What are the risks for her if she removes Bob's name without his agreement and submits the manuscript on her own?

PS: as a response to Captain Emacs' comment, Bob's only contribution was to say "why don't we study the causal effect of X on Y?" in an informal conversation. Alice did absolutely all the rest (literature review, design of the protocol, data collection, analysis, conference presentations, etc.). But there is no evidence of this, other than the fact that Bob would be unable to answer any question that goes into the detail of the paper.