The phrase is often used when referring to compromises and alludes to making a choice between two options that could never be reconciled. In other words, the two options that are mutually exclusive.
I learned this concept when I was in school. Strangely, our leaders in the PAP did not understand this concept.
Mr LKY proposed the office of the elected President. This person is voted by the people and is given wide power to block the use of past reserves. This power was useful in case an alternative government is elected into office in Singapore.
He did not anticipate that the first elected President, Mr. Ong Teng Cheong, would carry out his duty diligently as spelled out in the constitution and question how the current PAP government was spending the government funds and reserves.
The problem became more complex because the concept of current and past reserves was not clearly defined. It was a very bad idea to start with.
After President Ong, the next two presidents were more relaxed about allowing the government to do what it wanted. This did not solve the problem entirely.
Some of their actions taken by the government appeared to contradict what was stated in the constitution, especially in the role of the elected president. One concerned citizen and politician, Mr. Kenneth Jeyaretnam, brought up a case in court that the government was acting against in constitution in granting a loan to the International Monetary Fund without the approval of the President.
I hope that this embarrassing situation will teach our leaders about the concept of "you can't have the cake and eat it". If they want better governance and control over the use of the past reserves, they have to abide by the constraints and allow the elected president to do his duty. If not, it is better to remove the powers and responsibility from the elected president.
They cannot have a president to check an alternative government, and expect the president to close both eyes when the unauthorized spending is carried out by the current PAP government.