By Patricia Zengerle

WASHINGTON (Reuters) – The White House must decide this week whether to clear the release of a classified memo written by Democrats. The document aims to rebut a Republican memo alleging FBI and Justice Department bias against President Donald Trump in a federal probe into potential collusion between his 2016 presidential campaign and Russia.

The following explains what is in play in a partisan dispute roiling Washington.

WHAT IS THE REPUBLICAN MEMO?

The four-page document was commissioned by Representative Devin Nunes, the Republican chairman of the House of Representatives Intelligence Committee, and released on Feb. 2.

It accused senior Federal Bureau of Investigation and Justice Department officials of not revealing that portions of a dossier of alleged Trump-Russia contacts used in seeking a secret Foreign Intelligence Surveillance Court warrant to eavesdrop on former Trump campaign aide Carter Page were partly paid for by Democrats.

It also portrayed former British spy Christopher Steele, who compiled the dossier, as biased, saying he “was desperate that Donald Trump not get elected and was passionate about him not being president.”

WHAT IS THE DEMOCRATIC MEMO?

In late January, House Intelligence Committee Democrats said they had drafted their own classified 10-page memo about the investigation of Russia and the 2016 U.S. election. They said their document would counteract what they criticized as “highly misleading” assertions in the Republican memo.

While Republicans on the intelligence panel initially blocked Democrats’ effort to release their memo, they joined Democrats on Feb. 5 and allowed the Democratic document to be sent to the White House for Trump to decide whether to release it.

WHY DOES IT MATTER?

Democrats say the Republican memo could be used by Republicans to try to undermine the credibility of Special Counsel Robert Mueller’s federal investigation into possible collusion between Trump’s presidential campaign and Russia to help him win the election.

Mueller’s investigation also is examining whether Trump has committed obstruction of justice by trying to thwart the Russia probe, which has cast a cloud over his year-old presidency.

Democrats say Trump’s allies hope to use the memo to protect Trump. They believe it could give the president, who fired FBI Director James Comey in May, an excuse to fire Deputy U.S. Attorney General Rod Rosenstein, who hired Mueller, or even to dismiss Mueller himself.

U.S. intelligence agencies have concluded that Russia interfered in the 2016 presidential campaign using hacking and propaganda, an effort that eventually included attempting to tilt the race in Trump’s favor.

Moscow has denied meddling and Trump has denied collusion or any obstruction of justice. He has called the investigation a witch hunt.

WHAT ARE THE POSSIBLE CONSEQUENCES OF THE MEMOS?

The release of the Republican memo widened the divide between Democrats and Republicans, possibly diminishing the credibility of any findings by congressional panels that are also investigating the Russia matter.

Its release also threatened to weaken long-standing cooperation between lawmakers and intelligence agencies, which have shared classified information with Congress with the understanding that it would never be made public.

If Trump declines to declassify and release the Democrats’ memo, it could set up a dispute that would pit the White House and many of Trump’s fellow Republicans in Congress against Democrats, law enforcement and intelligence agencies.

WHAT ROLE DOES THE INTELLIGENCE COMMITTEE PLAY?

The House Intelligence Committee is one of three congressional panels investigating the Russia issue even as Mueller pursues his criminal probe. The dispute over the memo has deepened a partisan divide on the panel, whose Democratic members accuse Republicans of seeking to focus on the Steele dossier and Page surveillance to protect Trump. Republicans say they merely want to publicize wrongdoing.

(Reporting by Patricia Zengerle; Editing by Peter Cooney and Frances Kerry)