There are two reasons that Britain and France are part of the UNSC.
Firstly, Britain and France almost always vote in tandem with the United States. Thus, they are mere appendages of the US.
Secondly, Britain and France obtained their seats on the UNSC under a grandfather-type law. Since Britain and France were strong naval powers in the past, they were able to obtain a UNSC veto at the end of World War II.
Finally, the US, China, and Russia have not made a concerted effort to kick Britain and France out of the UNSC. The US wants its two little allies to vote along with the US. China understands the Europeans do not have an independent policy. Thus, it matters not whether the US has one vote or three votes.
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However, all of the factors that allowed Britain and France to sit on the UNSC do not apply to India.
The world does not recognize India as a major power.
Thus, India has failed repeatedly in its quest for a permanent UNSC seat.
As I have enumerated, there are many weaknesses that India probably cannot overcome.
In modern times, the countries of the world will not permit another UNSC seat without superlative qualifications.
1. India is simply too small a country. With a landmass of only 1/3rd of China, you are not China's equal.
2. India is constantly antagonizing China. Since China holds an existing permanent veto, China will keep vetoing India's attempt to obtain a UNSC seat.
3. India is an incredibly poor country. China's nominal per-capita GDP is five times higher than India's.
4. China's technology is light-years ahead of India's. China's semiconductor fab technology is at 28nm. India has ZERO semiconductor fabs. Your technology is NO nanometers.
As you can see, India is extremely unlikely to ever obtain a UNSC permanent veto.
UNSC is a dead instrument,
1,Once India expands its N sub fleets carrying 10000 Km N ballistic missiles,
2,expands its economy to global top 3 & have robust economic engagements with all countries , with a huge forex reserve,
3, Develop its own 5th gen stealth fighters, MBTS etc, etc,
No one can touch india in UNSC
Also no UNSC move will harm India's potential.
It is not UNSC seat which allowed the oil rich Saudis & underling Turks to fund ISIS.
Its not UNSC seat which allowed Putin to interfere,
Its not UNSC seat which made US, britain, France, china a mere useless bystanders in the war against ISIS in Levant,
So why worry over it??
India was sanctioned for its non NPT N weapon status till a few years back,
What happened?
Once economy picked up , NSG waiver came, now NSG membership awaits,
Also we are inside MTCR, while china's veto power still couldn't allow it entry into MTCR!!
So maintaining a balanced diplomatic relation with every one, while developing economy, military itself will do for india, what any UNSC seat can't do.
besides no one knows what is your true GDP, since most of your stats are forged, and there are many nations that have higher GDP per caipta than you,
Also no UNSC seat will allow you to swallow south china sea, if you dont have enough naval muscle & diplomatic , economic wherewithall to defend it.
Most of chinese diplomatic moves are infantile rants, that doesnt carry any conviction!!
If you want to know your true diplomatic weight, just recount the occasions china used its veto in UN in any definitive manner during gulf war , Kosova war, Afgan invasion, Vietnam war etc, etc, and used its military-diplomatic, UNSC muscle to bring about an out come favoring you,
All your veto power is used to safe guard international terrorist like hafeez Saeed from prosecution!!!
Most of the time china abstains in UNSC resolutions, because it knows fully well the "kick in the ass" it will get if it uses its veto to stall US-France-Britain combo!!!
And Russians dont trust you either , SO china can never expect full fledged support from them for its imperial desires , as well .
So other than blissfully abstaining you cant do anything in UNSC,
Same will be the case if india has a veto now, Without power-diplomatic equations it too will naively abstain and become a laughing stock paper tiger like china!!
In Kosova war the US bombed your own embassy, & you couldn't wag your little finger with your Veto!!!
lets see how you use your UNSC veto to swallow south chin sea!!!