There is no easy way to attack Bitcoin and take control of it - become the powerhouse that makes the most money from it. That investment wouldn't pay off in the end.
It's a bit different if your goal is try to destroy Bitcoin or inflict as much damage to it as possible. In that case, the most vulnerable category would be miners. You would need a global action on a massive scale against mining companies. Stop their operations, confiscate their hardware, and stop the production of new blocks and confirmation of transactions.
Bitcoin can recover from that with a very bloody nose. The mining difficulty would drop, making other machines suitable to take over the process from those previously confiscated. But than the global police would have more powerful hardware than the honest miners.
All this is sci-fi and will never happen. Our leaders can't even make up their mind if it's ok to kill 35.000 innocent people or not, let alone come to an agreement and organize something on a massive scale like an attempt to destroy Bitcoin.
...not mentioning that since those billions would be taxpayers' money, if the government is a democracy, it will be the last thing (use of money) they'll approve before getting changed and the preorders canceled.
That taxpayer money could be used much more wisely. For example, on fighter jets and massive bombs intended to be dropped on a small piece of land. You know, for democracy and preserving freedom.