Mr Bush has consistently dismissed such reasoning in the past, arguing that Islamic militants had hated the US long before it invaded Iraq or Afghanistan.
Our correspondent says the report gives backing to the White House view that a victory in Iraq would be a big prize with fewer enemy fighters inspired to carry on.
There is also mention of real successes against al-Qaeda.
But the overall picture, including the assertion that the Iraq conflict has become a cause celebre for jihadists, is not terribly comforting for Mr Bush and could be a setback in the elections, our correspondent adds.
Other key points of the report include:
- Militants, although a small percentage of Muslims, are increasing in both number and geographic dispersion
- If this trend continues, threats to US interests globally will become more diverse leading to increased attacks worldwide
- Militants consider Europe an important venue for attacking Western interests
- The loss of key leaders in rapid succession would probably fracture al-Qaeda into smaller groups that would pose, at least for a time, a less serious threat to US interests.