If one were to go by Article 156 of the Constitution then the Manmohan Singh government was well within its
rights to sack the governors of Goa, Gujarat, Haryana and Uttar Pradesh. The legal position is that a governor
can "hold office during the pleasure of the President."
But the controversial easing out of governors and replacing them with new appointees has more to do with politics than anything else. The UDA government's explanation as articulated by minister of state for home, Prakash Jaiswal, was that the four governors had to be given the marching orders since they were too aligned to the RSS and could not be expected to discharge their functions in an objective manner. At least, one governor, Vishnu Kant Shastri, of Uttar Pradesh, proclaimed that he was proud to be a member of the RSS, proving that there was some truth in what both Jaiswal and the Congress party were alleging.
But that does not provide any justification for axing the governors. Neither does the explanation that the NDA government too had replaced the constitutional heads in some states when it assumed power hold good. When a governor is given marching orders for purely political reasons, it only serves to erode the credibility of the Raj Bhavan. By forcing the President's hand and getting him to seek the resignations of these four governors, the Manmohan Singh government has set an unhealthy precedent. True, the government did write to the governors trying to persuade them to demit office and "when all else failed" it was recommended that the President issue the sack notice.
Here it must be stressed that one is not trying to justify the appointments of these governors in the first place by the previous government. The choice of a gubernatorial candidate has not been clearly defined despite it being a much debated issue. Although the Sarkaria Commission did make some recommendations, the political masters find it convenient not to appoint a man who is independent and impartial despite having political leanings.
This is because those in power want a pliable man in each state--someone who will act at the bidding of the government of the day. So the NDA set up men with strong BJP/RSS inclinations in the various Raj Bhavans. Rama Jois in Bihar and Madan Lal Khurana in Rajasthan were such appointments and of course Vishnu Kant Shastri in Uttar Pradesh. The UPA has proved it's no better by axing four governors and replacing them with their own men in less than two months of assuming office.
To ensure that that those appointed as governors survive regime changes one needs to introduce a methodology with constitutional backing that ensures that those appointed are men of unquestionable integrity. But can there be a formula? There may not be one in this age of coalition politics. And as the constitution stands, there is nothing that prevents a government from axing a governor. The Manmohan Singh government has exercised that right and has done it without offering any credible reason for its action.