SCENARIOS: Major foreign policy issues facing next president

(Reuters) - The next U.S. president, whether it is Democrat Barack Obama or Republican John McCain, will face a full plate of foreign policy challenges.

Here are some of the top issues:

WAR ON TERRORISM AND AL QAEDA

Al Qaeda militants who have gained strength in the tribal region of Pakistan are an increasing U.S. concern. Obama has said that if the United States has top al Qaeda members in its sights and Pakistan is unwilling or able to act, the United States should take them out. McCain has criticized Obama's willingness to say that out loud and has said he would work with the Pakistani government to pursue al Qaeda.

AFGHANISTAN

Both McCain and Obama have said they would put more focus on defeating the Taliban insurgency in Afghanistan and eradicating al Qaeda from Pakistan's borderlands.

Both candidates have said they would boost U.S. troop strength in Afghanistan from the current 32,000.

The Bush administration is considering talks with "reconcilable" Taliban elements as part of its review of Afghanistan strategy. But no decision has been made and it will be up to Obama or McCain to decide whether to go ahead.

IRAQ

Obama, who opposed the 2003 invasion of Iraq, has called for a 16-month timetable for withdrawing U.S. troops from Iraq to enable a greater focus on Afghanistan. McCain has rejected timelines, saying U.S. troops should remain in Iraq as long as they are needed.

IRAN

Both Obama and McCain have said Iran cannot be allowed to acquire a nuclear weapon. Obama favors tough-minded diplomacy with Tehran and has said he would be willing to meet with Iran's leaders without preconditions, though there would be extensive preparations before any such meeting. He has said his promise to meet with Iran's leaders does not necessarily mean he would sit down with Iranian President Mahmoud Ahmadinejad because he is not the most powerful person in Iran. McCain has called Obama's willingness to meet with Iranian leaders "naive" but does support lower-level engagement.

RUSSIA

Both McCain and Obama condemned Russia's August invasion of Georgia and both favor allowing Georgia and Ukraine to join NATO. McCain emphasizes harsher rhetoric toward Russia and has called for kicking Russia out of the elite Group of Eight club of rich nations.

MIDDLE EAST PEACE PROCESS

There has been little sign of progress in talks between the Israelis and Palestinians launched by President George W. Bush in Annapolis, Maryland, a year ago. But both McCain and Obama have promised a vigorous effort at Middle East peacemaking. Both have also vowed staunch support for Israel.