I believe that the direct effect of the passage of the Seventeenth Amendment is that it improved representation of the people, because now they were able to directly choose Senators, which made the whole voting process a lot democratic.
I'll do you even better, I'll give you at least 5 or 6 reasons.
1. Rise of Al Qaeda (Founded in 1988 and funded during the Iraqi war by several nations including Saudi Arabia to bring down Shia government there)
2. U.S intervention is several nations causes outburst of common folk who join Al Qaeda.
3. Al Qaeda becomes involved with other groups who are now starting to form.
4. Syrian war intervention by the U.S, several other allied nations and Russia start several groups, that of which was once apart of Al Qaeda, the Islamic State of Iraq and Syria.
5. Progress in illegal trade, alignment with other groups and production of weapons compensates these groups.
6. The usage of speeches presented by the likes of demagogues as well as force recruitment and evening kidnapping gain more members to the cause.
While Congress had the right to regulate all forms of American currency, the Articles failed to call for a singular form of currency. This meant that the national government could print money, but each state could as well. Consequently, America had no uniform system of currency which made trade between the states, and with foreign entities, much more difficult and less efficient.