Will a "failed" poly result bar me from federal employment?

[Sturnidae in flight]

Hi all:

Thanks for considering this question. I'm applying for a position with a local agency; meanwhile I have my eye on eventual federal employment as a special agent with the FBI, DEA, or ICE.

On my first poly with this west coast agency- which I went in and told the truth on - I received an inconclusive result. I requested to take it again. I received a letter granting my request. I have no faith in this exam and would not be surprised if they "fail" me this next time around.

If I fail the exam the next time around in September with this local agency, how will that affect my chances of federal employment?

This mess has affected my health and outlook. I'm losing weight and, probably, losing perspective. Like so many others, I've invested a lot of my life in pursuing this endeavor. It has been my dream and now I can see it slipping through my fingers, for something I have no control of and didn't lie on. Any advice you can give would be very much appreciated.

(Note: apologies if this question about failure with a "local" agency has been covered before. I tried to search forums first but couldn't get results)