* Obama faces pressure for more aggressive foreign policy
* Could try to regain support by actions in foreign affairs
* Faces tough challenges, struggle to make a mark
By Timothy Heritage
BRUSSELS, Nov 3 (Reuters) - U.S. President Barack Obama could turn to foreign policy as a way to claw back popularity after his midterm elections setback, which has left him weakened in domestic politics.
Obama will face pressure to adopt a more aggressive foreign policy, such as using more force in Afghanistan and keeping troops there longer, after Republicans made gains in the Senate and captured the House of Representatives.
But foreign policy is also an area where Obama could have a relatively free hand and he is likely to start efforts to rebuild his image abroad when he begins a trip to Asia on Friday.
Bill Clinton fought back to win a second term as president after heavy Democrat losses in midterm elections in 1994, but Obama can expect no easy victories in the foreign policy arena.
"One classic scenario would be that the president, having lost his majority in Congress, would focus more on foreign policy. This is something that Clinton did to an extent. The problem for Obama is that there is no low-hanging fruit on foreign policy," said Thomas Klau, a Paris-based analyst with the International Council on Foreign Relations think tank.
"Afghanistan remains very difficult, more difficult domestically. Neither Iran or the Middle East conflict or indeed Pakistan or other geographical places suggest that a stronger, more sustained personal engagement from Obama would be very likely to usher in short-term breakthroughs or benefits."
Global intelligence company STRATFOR said the United States remained the global superpower and a president who is weak at home is not by default weak abroad.
"In fact, a weak president often has no options before him except foreign policy," it said.
WHAT ARE OBAMA'S FOREIGN POLICY OPTIONS?
It is not clear where Obama might choose to make his mark but he faces challenges and pressure to adopt tougher policies almost wherever he looks.
Waheed Omer, a spokesman for Afghan President Hamid Karzai, said the relationship with Washington would continue regardless of the elections and Taliban spokesman Zabihullah Mujahid said the outcome would not affect its intention to keep fighting until all foreign forces leave Afghanistan.
But Daoud Sultanzoy, a U.S.-educated Afghan analyst, said Obama may have to take another look at strategy in Afghanistan, where U.S.-led NATO troops are bogged down fighting the Taliban.
"Obama will need to reverse from some of the policies, use some of the Republicans' values and basically reach out to them for a bipartisan (deal)," he said. "The Republicans want use of more force, longer (troop) presence and intense confrontation with terrorism."
Other analysts said the Republicans could also push for a review of policy on Pakistan.
Pakistani political analyst Hasan Askari Rizvi said Pakistan's government would face new pressure to crack down harder on Afghan militants who cross the border to attack NATO troops in Afghanistan.
"They will be raising more questions about the government's performance, about cross-border movements and about why the situation is not improving in Afghanistan," he said.
Talat Masood, a retired Pakistani general and analyst, said: "The only fear that I have is that Republicans have a far more aggressive foreign and defence policy, which has already been demonstrated in (former President George W.) Bush's time."
"Expectations from Pakistan will increase and I expect there will be greater demands from Pakistan to take tough action against militants and there will be greater scrutiny," he said.
MIDDLE EAST HEADACHE
The Republicans could also try to push North Korea's nuclear capabilities up the agenda.
"If anything, North Korea might find it more difficult to get back into the negotiating framework with a stronger Republican representation in Congress," said Paik Hak-soon of the Sejong Institute near Seoul in South Korea.
A headache looms for Obama in the Middle East, where former Israeli diplomat Yoram Ettinger said the election outcome had strengthened pro-Israeli elements in Washington.
"This is going to constrain immensely the manoeuvrability of the president, who is generally pretty critical (even) negative towards Israel, which would require the president, in my mind, to limit his pressure on Israel," he said.
One country where the heat could be turned down is China because the elections delivered a business-friendly Congress. Democrats accused China during the campaign of taking U.S. jobs by suppressing the value of its currency and rigging its economy to favour Chinese state firms.
In Europe, the Republican gains could help sharpen the divergence with the U.S. government on financial regulation, climate change and aspects of foreign policy.
Ruprecht Polenz, head of the lower house of parliament's foreign affairs committee in Germany, said it would now be more difficult to secure U.S. ratification of the START disarmament treaty with Russia and Washington would be more self-absorbed.
"It is on the whole not a good thing for the world. No major international conflict can be resolved without the United States. So we must be ready for Europe to engage more boldly (in global diplomacy)," he said. (Additional reporting by Emma Graham-Harrison and Sayed Salahuddin in Kabul, Zeeshan Haider in Islamabad, Jack Kim in Seoul, Luke Baker in Brussels and Andreas Rinke in Berlin)