Victory for Tony Nicklinson at the High Court would be a landmark ruling in a right-to-die case and would alter the UK's murder laws.
The locked-in syndrome sufferer wants any doctor delivering him a fatal dose to have a "common law defence of necessity" against any possible murder charge.
Current legal guidelines suggest only family members or close friends, who are driven by compassion, are unlikely to be prosecuted for assisting a suicide.
A second case of a locked-in syndrome sufferer, which is also set for a High Court judgment, could also shift assisted suicide practices.
The man, referred to as "Martin", wants volunteers to take him to Swizerland's Dignitas clinic as his wife is unwilling to help end his life, despite backing his right to die.
A ruling in his favour would widen the pool of people who would be unlikely to face prosecution for assisting such a death.
The Courts have left it up to Parliament -so what next for the right to die issue?
Tony Nicklinson, who was left paralysed by a catastrophic stroke, has lost his High Court battle to have a doctor end his life.