States wrestling with congressional redistricting have their eyes on Virginia, where new district lines are turning into battle lines in a debate that could wind up in court.

For the first time in the state's history, Republicans control the state Legislature and are using redistricting to create Republican-friendly districts. The new border drawn between the state's neighboring 3rd and 4th districts has become a lightning rod for the controversy, because the new boundary appears to have been drawn along racial lines.

The Supreme Court, in a series of rulings on North Carolina's redistricting, has said that states cannot use race as a factor in redistricting. However, the court said that states could use redistricting for political purposes.

The question in Virginia is whether new district lines that specifically change the percentage of African-American voters in a district was racially motivated or done to improve the chances of Republican candidates.

At issue is Virginia's largely African-American 3rd District, which is represented by Rep. Bobby Scott, the state's only African-American congressman. The state redrew Scott's district so that it encompasses even more black voters, grabbing 5 percent of the black voters from the neighboring 4th District.

Scott's district is now 57 percent black, while the more diverse 4th District lost a block of black voters — a shift that helped Republican Randy Forbes win a recent special election held after the death of Norm Sisisky, a Democrat who had represented the 4th District for 10 terms.

Scott said he didn't need the extra black voters in District 3, but that taking the black voters from the 4th District made it more difficult for black candidates to succeed there. Democrats are crying foul and threatening to take the case to court.

According to the Supreme Court rulings, Virginia cannot build a district for solely racial reasons. But it is completely legal for states to redistrict for political purposes. It's a gray area, and with Virginia being one of the first states to file its redistricting plan, it's a case that has the rest of the country watching closely.

Republicans now control more state legislatures than they did in 1990, with many of those states gaining in population over the past decade and now requiring redistricting. The Republicans stand to gain up to 10 seats in the House. The fight for those seats has Democrats and Republicans rallying their forces for a high-stakes war being waged state by state.

Democrats predict that the ratio of representatives from the two parties will remain the same, but that could change depending on how the courts rule as the redistricting plans are filed.

Fox News' Brian Wilson contributed to this report.