Under the articles of confederation, why didn't the federal government enforce the laws? the states were the ones that enforced the national laws. there was no executive branch of the government. there was no national police force. there was no president.

I believe the answer is there was no executive branch of government. 

The difference between a federation and a confederation, is that in a confederation, it is more of loosely tied together states that can leave at any time. Just look at the EU with Brexit. The UK is exercising it's right to leave. In an example of a federation, look at the US. The states aren't allowed to claim independence because it is against the laws. It's also tied together under a firm federal center.