By Prak Chan Thul
PHNOM PENH (Reuters) - Cambodia's king has pardoned Sam Rainsy, a senior figure in the opposition to long-serving Prime Minister Hun Sen, and he will now be free to return from self-imposed exile in France and campaign in a general election at the end of the month.
Rainsy was sentenced to 12 years in prison in 2010 on charges of spreading disinformation and falsifying maps to contest a new border agreed by Cambodia and Vietnam.
U.S.-based Human Rights Watch said at the time the charges were political and that they showed Hun Sen, in power for 28 years, was "no longer interested in even the pretence of democracy".
In a letter to King Norodom Sihamoni requesting the amnesty that was read out on television on Friday, Hun Sen said his decision was based on "national reconciliation" and Rainsy's return would ensure the election was democratic and free.
In an announcement on television, Hun Sen said Rainsy had sent a request to him on June 13 asking that he be allowed to return without fear of being thrown into prison.
"He is able to return without being arrested," a senior lawmaker from the ruling Cambodian People's Party (CPP), Cheam Yeap, told Reuters.
"The CPP doesn't want to cause any fight. The CPP's principle is that we want national reconciliation, peace and stability, we have the same blood. Sam Rainsy was stubborn in the past."
On June 8, after a CPP-dominated committee expelled 29 opposition lawmakers from parliament, the U.S. State Department called for "a political process that includes the full participation of all political parties on a level playing field".
"This (pardon) means the CPP wants to reduce the pressure before the election. With all this pressure, the opposition party has actually been seeing some benefit," said independent analyst Chea Vannath.
The party bearing Sam Rainsy's name merged this year with two others to form the Cambodia National Rescue Party (CNRP) to fight the election. The parliamentary committee had said that made the 29 lawmakers ineligible to sit for the old parties.
This week, lawmakers in Washington started a process that could lead to a cut in U.S. aid to Cambodia of about $70 to $80 million a year unless the election is seen to be free and fair.
(Editing by Alan Raybould and Ron Popeski)