Sen. Mark Warner (D-Va.) (Alex Wong/Getty Images)

RICHMOND — Former governor Mark Warner remains a force in Virginia politics, opening a 25-point lead over Republican challenger Ed Gillespie in the early stages of the U.S. Senate race, a new poll shows.

In a Roanoke College Poll of 556 voters, Warner (D) leads Gillespie 47 percent to 22 percent, which is a slight improvement for the longtime GOP strategist who was 27 points down in February but still within the poll’s margin of error.

The poll, which also questioned voters on a host of national and statewide issues, found 75 percent of voters don’t yet know enough about Gillespie to form an opinion — the same as in January. Libertarian candidate Robert Sarvis is unknown to 81 percent of voters.

In one bright spot for Gillespie, independents report that they tend to slightly favor Republicans over Democrats on Election Day.

“While it is still early, Gillespie needs to begin to introduce himself to Virginia voters. Winning the nomination did not lower the percentage who essentially do not know who he is,” said Harry Wilson, director of the college’s Institute for Policy and Opinion Research. “Gillespie needs a lot of money and positive name recognition to even begin to compete.”

Ed Gillespie (Steve Helber/AP)

Warner, a former governor seeking a second term in the Senate, is ahead in the fundraising contest as well, according to campaign finance reports released last week. Outside groups have said they are unlikely to jump into the race on Gillespie’s behalf unless he can narrow the margin.

When it comes to the issue that has dominated General Assembly debate for months, voters are split on whether the state should expand Medicaid to 400,000 residents (46 percent say no, 42 percent yes), but a majority (61 percent) do not want Gov. Terry McAuliffe (D) to unilaterally expand the program despite his promises to do just that.

McAuliffe’s disapproval rating is up to 27 percent — an 11-point jump from January — while his approval rating is nearly unchanged at 38 percent.

In time for the start of former Gov. Bob McDonnell’s (R) trial next week, most of those surveyed (54 percent) think the Republican did something wrong when he accepted gifts and favors from Jonnie Williams of Star Scientific.

The poll also asked voters about the resignation of state Sen. Phillip P. Puckett (D-Russell), which flipped control of the Senate to Republicans and stymied McAuliffe’s Medicaid plans, but most didn’t have an opinion.

The vast majority of voters (76 percent), however, called both McDonnell and Puckett’s actions “typical of elected officials” rather than uncommon events.

Turning to national issues, the poll looked at potential 2016 presidential match-ups and found former Secretary of State Hillary Rodham Clinton (D) would beat possible Republican hopefuls New Jersey Gov. Chris Christie, Sen. Rand Paul of Kentucky and Rep. Paul Ryan of Wisconsin by at least 10 percentage points.

President Obama remains underwater with voters — 53 percent of whom disapprove of his job performance — and his unfavorable rating has increased to 50 percent. Congressional approval remains very low at 7 percent, the poll found.

Voters are most worried about economic issues, including unemployment and taxes, while immigration, foreign policy, gridlock and health care also areas of concern.

About half of voters surveyed oppose a plan by some House Republicans to file a federal lawsuit seeking to declare Obama’s executive orders an unconstitutional power grab by one branch of the government.

The poll was conducted by phone from July 14 to July 19 and has a margin of error of 4.2 percent.