Purpose of the bitcoin nodes are to ensure the integrity of the network by regulating which blocks/tx's are valid, so the invalid blocks or tx's can't make it to the ledger.
Discussion
I come back and repeat, governments cannot do anything against BTC even having nodes. They can only continue manipulating the brains of people who living in fear and don't really understand the meaning of decentralization and how #bitcoin works.
Yes they can, as much as any other user running a node can.
It's the beauty of #Bitcoin, it doesn't discriminate users, even if the user is government.