Yes especially with a 5 transactions per second capacity network and a cloud like block chain(distributed nodes and mining pools around the world)  with a cloud like vault containing the coins(private keys). the whole world if come together to shut down bitcoin they will not succeed however we all know that united front global nations is impossible it also won't work the other way, not the whole network of bitcoin united can cripple an entire nation's economy.
As the coins are being widely spread there is not much of a strong support in any particular country, you can not allocate enough liquidity in exchange for a large amount of bitcoins with the current marketcap. $20B is nothing compared to the financial back bone of most of the countries.

One of the promising benefits of decentralized currency, you can not use it potentially to do harm more than doing good and balancing the justice between the tyranny of world powers against the peaceful countries.

Reason why the idiots of thinking rooms of governments should start recommending their leaders to accumulate as many bitcoins as they can because since bitcoin is no longer a fancy joke and piece of code and has real impact on different levels of society who ever holds more can do more whether good or bad in the future when price per bitcoin is well above $15K.

It can bring country to it knee as Is decentralized that is people can produce more bitcoin without government knowledge and that creates inflation in the country as government cannot control the currencies in the circulation.the only way government can control it is through regulatory agency or body but I see no one is trying to do that except china.

Nowhere bitcoin has gained the potential as a mainstream currency, so it won't affect the economic development of a country. It would serve as a good alternative to serve the financial technology through advanced blockchain technology. When the same get used in several sectors the development will be much than the present. So it makes the country stand strong and grow in economy.

It won't happen. Bitcoin cannot bring any country on its knees because its not even adopted by mainstream. And even if is mass adopted, the government will not let bitcoin takeover their financial industry like banks because they will be useless if bitcoin became the main currency. Banks are controlled in how much money they can create by Central Banks and Financial Regulators. Banks have controlled the supply of money for so long that they won’t give it up easily. So bitcoin will not bring any country to its knees as far as the financial industry is concern IMHO.

YES it CAN  !! Maybe thats the reason why many countries are afraid of supporting it because it can collapse their economy with traders and whales manipulating its price

Unless btc become international currency officially,I do not think it can bring any nation to it knees.
The currency of any country is pegged against dollar and unless dollar fail or a national currency is pegged with bitcoin,chances of happening that is negligible.

Because of the value of bitcoin today that is why you come up with this topic, but I think even if the value was very great that other fiat money it will not mean any countries down to it's knees because no country is holding bitcoins and it is not controllable by any of that country in fact if a country is using bitcoin they are just manifesting the use of it and because direct transaction was really not a much option with bitcoin the exchanging of fiat to bitcoin or bitcoin to fiat was taxable by some country!

Yes but it is not that easy because these corrupt politicians may pass a bill to ban bitcoin with some false accusation to save their backside and also try their best to stop bitcoin from over taking their currency but all i can suggest is bitcoin will not replace any particular currency but it will as best alternative to any fiat.

but i think currently still there is not a single country who have accepted bitcoin as legal currency. but i think if future there are more chance that government will accept bitcoin as legal currency, because the new generation are taking more interest in bitcoin.