The phrase "a legitimate base" is correct and usable in written English.
It can be used when referring to a valid or acceptable foundation for an argument, theory, or system.
Example: "The research provided a legitimate base for the new policy recommendations."
Alternatives: "a valid foundation" or "an acceptable basis".
It will not have a legitimate base".
Violation of the trust gives the people a legitimate base for resistance.
The real reason he could not be president, he said, was that he had never developed a legitimate base.
Buddhism held a great appeal for the Wei rulers, as it gave their leadership a legitimate base in a multiethnic society.
Yet underpinning the efforts by Mr. Cuomo and Ceres is the belief that such a view is not, in fact, a legitimate basis upon which to base corporate strategy — and that companies need to be forced back into line.
F.B.I. officials said that although they were sympathetic to the C.I.A. officer and convinced of his innocence, they had a legitimate basis to investigate him based on available information and used legally accepted techniques.
She has a legitimate geographic base, having represented an Albany-area Congressional district in a part of the state where her family is prominent.
I acknowledge a legitimate moral base underlying such Freud-bashing: the human consequences of his scientific errors, and his often ugly interpersonal relations.
Mr Ward points out that, as a charity, the foundation is entitled to use "emotive or controversial material", but only as long as it is "factually accurate and has a legitimate evidence base".
It's a lot easier to create hardware prototypes when you have a legitimate starting base.
After that, if you haven't built a legitimate fan base made up of people who don't share your DNA or your DMA, your crowdfunded career is finished.
