Gov. Robert F. McDonnell (R) vetoed a bill Friday afternoon that would have drawn new state legislative boundaries in Virginia for the next decade, saying he believes it violates state and federal law.

The maps had been part of a deal hatched between the majority parties in the divided General Assembly in a way that protects incumbents.

The Republican-controlled House of Delegates approved the plan by a largely bipartisan 86 to 8 vote, but the Democrat-led Senate adopted it on a straight party-line vote of 22 to 18.

The bill will now go back to lawmakers, who are expected to return to Richmond on April 25 to consider McDonnell’s veto and finish drawing congressional maps.

A veto will probably anger the majority parties in the General Assembly, including House Speaker William J. Howell (R-Stafford), McDonnell’s powerful ally and longtime friend.

The plan called for Northern Virginia to gain a new senator and three new delegates, all in the region’s growing outer suburbs, to accommodate population shifts revealed by the once-a-decade census.

This post has been updated since it was first published.