In short, each nation cannot effectively defend itself militarily against an invader or aggressor by ignoring the other, apart from the sheer stupidity of going it alone. The Five Powers Defence Treaty (FPDT) has shown and taught Malaysia and Singapore the need for combining and coordination their air defence, TOGETHER.
The politics between the two might be rotten but that's a reflection of historically antagonising personalities - okay, throw in a bit of racial and jealousy issues as well, including what the Chinese (Penang Hokkien) would call 'knere k'ang'.
'Knere' means 'jammed' whilst 'k'ang' means 'hole', thus the phrase 'knere k'ang' translates loosely into 'unresolved disagreeable matter'. or more figuratively 'unhappiness-dissatisfaction over unresolved disagreeable matter'.
Between Singapore and Malaysia, yes you bet, there are lots of 'knere k'ang' such as the price of raw water that Malaysia sells to Sing (in contrast to the price of treated water Sing sells back to Malaysia), the 'crooked bridge' (only a making of Mahathir himself), Pedra Branca, airspace and today, territorial waters (the last two most probably 'makings' of Mahathir again).
apart from National car No 3, Mahathir wants to build an island on Middle Rocks (see rocks behind Pedra Branca in above picture), whilst his government tells students to cough up on their PTPTN loans
There also used to be the KTM land but which we have since learned was already sold off by actually the Mahathir government in the 90's but was left unresolved to practical working levels until Najib's time, wakakaka.
Mahathir has always had a bad relationship with Singapore, but which we needn't burrow into at this stage other than to say Singapore herself hasn't been exactly an angel in her relationship with a by-far more placid Malaysia under the previous two PMs.
Leaving aside the decades-long unresolved price of water, crooked bridge, an already lost Pedra Branca and control of the adjoining airspace, the current spat, with Koon T'au Boe (4) being waved by Sing at Malaysia, I reckon both Sing and Malaysia have reached amazingly low levels of childishness between two fraternal neighbours - yes, the Malay versus Chinese attitude is there too in Malaysia's new assertiveness of her sovereign rights in its airspace and likewise with Sing in her territorial waters.
Our Wisma Putra hasn't been exactly brilliant by proposing that both nations keep clear of the 'disputed waters' until a resolution has been agreed upon.
Isn't that just a bloody pathetic proposal because 'disputed waters' is exactly the reason why a 'dispute' exists and which must be rapidly-expeditously and amicably resolved so that its 'usage & by whom' may be agreed upon.
But alas, Saifuddin Abdullah being the 'Mr Nice Guy' of Malaysian politics has played the wrong game with an aggressive and assertive Sing.
is fCking Sing gonna bombard Malaysia?
Quite frankly, Sing in bringing out its RSS Independence and other vessels is behaving in a silly manner because the arena is such that those warships can easily be neutralised by Malaysia should such a dire need arise, but let's hope not.
But the diplomacy displayed thus far is pathetic on both sides, with a Malaysia at a loss for words whilst an aggressive assertive Sing thinks it can behave badly.
Egos must be dismantled and calmer men must talk amiably.