WASHINGTON — President Barack Obama’s expansion of the war in Afghanistan has eroded the power of the al-Qaida terrorists who attacked America in 2001 and the resurgent Taliban militants who gave them cover, according to his own government’s review.

The findings ensure that Obama will stay the course, with U.S. forces to remain at war through 2014.

U.S. troops will begin to leave Afghanistan in July, according to the report, the same timeline that Obama promised one year ago and has consistently upheld in recent weeks. But the scope and pace of that withdrawal remain unclear, and both are expected to be modest, given the enormity of the security and governance challenges in Afghanistan.

All the findings will be tested in the months and years to come. They form the basis not just of Obama’s war strategy but also his credibility with the American people on how this long, costly war is going, and when it will end.

The White House on Wednesday evening released a five-page summary of the newly finished, classified evaluation of the war strategy for Afghanistan and Pakistan that Obama unveiled to much fanfare in December 2009.

Obama will speak about the review findings at the White House this morning.