Gov. Bob McDonnell sent a letter to legislative leaders Thursday, urging them to take “immediate action” to either appoint judges or adjourn their special redistricting session so he can appoint them himself.

“The General Assembly has now been in regular or special session for over six months,’’ McDonnell (R) said. “The failure to timely complete redistricting and adjourn sine die is having a major negative impact on Virginia’s judicial system.”

The General Assembly, one of only two state legislatures empowered to pick judges, has spent months bickering over how to fill two vacancies on the Supreme Court, leaving the court unable to hear as many cases and forcing it to rely more on semi-retired senior justices.

Legislators in Virginia can select new judges as long as they are in session — either during the regular annual session, which concluded in February, or in one of the special, shorter sessions convened periodically to address one or two particular issues.

If they adjourn, McDonnell (R) is allowed to name justices to serve until the General Assembly returns for its regular session in January.

“Since the General Assembly is unable to agree on the selection of judges, I am prepared to perform my constitutional duties and appoint justices to the Virginia Supreme Court and judges to fill the several other trial court vacancies,’’ McDonnell wrote.

His office previously began accepting applications for people interested in becoming judges, and now will begin the evaluation process.

After failing to appoint any judges during the regular session this year, legislators returned in April and appointed a slew of lower court judges, including three new ones in Northern Virginia.

But six circuit court judges and at least four general district and juvenile and domestic relations court vacancies were left open — along with the two seats on the Supreme Court.

McDonnell (R) blamed the Democrat-led Senate for failing to agree to the House’s redistricting proposal or recommendation for judicial nominations.

“We’ll be back when we’re back — when there’s a reason to come back,’’ Senate Majority Leader Richard Saslaw (D-Fairfax) responded Thursday.

This post has been updated since it was first published.