The government created under the Articles lacked the power to tax. And the only way it could get money to pay its debts was to ask states to give funds. But states didn't have to or didn't give enough. So all in all the federal government was pretty weak.
The main reason the US Senate rejected the treaty of Versailles was because they feared that US involvement in the League of Nations would mean that American troops would be sent into Europe and settle European disputes.
