During an event in Winnipeg, Canada, Hillary Clinton said Congress should not seek to increase the level of sanctions on Iran “until we really know whether there’s something that we can get out of them.” (Reuters)

Hillary Rodham Clinton holds double-digit leads over potential Republican challengers Jeb Bush and Mitt Romney as the likely Democratic presidential candidate moves closer to entering the 2016 race, a new Washington Post-ABC News poll finds.

Although Clinton, Bush and Romney are all longtime politicians and members of political dynasties, registered voters are less likely to count that familiarity against Clinton. That is a good sign for Clinton, a failed 2008 presidential candidate and the focus of Republican criticism that her time has come and gone.

Clinton’s potential to make history as the first female U.S. president makes little difference to most voters and is a net positive for others.

The former first lady, U.S. senator from New York and secretary of state has said she is considering a second run for the White House. She joked about the anticipation surrounding her decision during remarks in Canada on Wednesday but did not offer hints about her thinking or the timing of a possible announcement. Democratic strategists say she is likely to enter the race in late March or April — some 10 months before the Iowa caucuses open the 2016 primary contests.

Clinton approaches the nominating season in a dominant position, leading Bush by 54 percent to 41 percent among registered voters and Romney by 55 percent to 40 percent.

Hillary Clinton ahead of GOP pack for 2016
Clinton leads in new 2016 poll

(The Washington Post/SOURCE: This Washington Post-ABC News poll was conducted by telephone Jan. 12-15, among a random sample of 1,003 adults. Interviews were conducted in English and Spanish on landlines and cellphones. Overall results have a margin of sampling error of plus or minus 3.5 percentage points; the error margin is 4 points among the sample of 843 registered voters. Sampling, data collection and tabulation by Abt-SRBI of New York. Full results and exact question wording and order is available at: www.washingtonpost.com/polls.)

Beyond Bush and Romney — the two Republicans who have made the firmest moves toward a 2016 run — Clinton holds equally large leads over other potential Republican hopefuls. She tops Rand Paul and Chris Christie by 13 percentage points each, and leads Mike Huckabee by 17 points.

Clinton’s husband, former president Bill Clinton, appears to create little drag on her potential.

Among all voting-age adults, more than 6 in 10 say the fact that Bill Clinton served as president has no bearing on whether they would support Hillary Clinton’s candidacy. And among those who say her spouse’s presidency will matter, 23 percent say it will make them more likely to support her, while 14 percent say less likely.

A presumed voter distaste for dynasties has long been seen as a barrier to Clinton should she run, along with a sense, off-putting to some, that Clinton’s candidacy has been a foregone conclusion for years.

Jeb Bush’s family connections are less benign. A 55 percent majority says the fact that Bush’s father and brother served as president would not make them more or less likely to support him. But among those for which this will be a factor, it runs in a negative direction by 3 to 1.

Romney’s 2012 bid for the presidency as the Republican nominee makes no difference for just over 6 in 10 respondents. But among those for whom it does matter, about twice as many say it makes them less likely to support him.

Two-thirds of Americans say that the potential for Clinton to be the first female president makes no difference in their decision to support her. Those who do put weight on this see it as a positive factor, by more than 2 to 1.

Partisanship and gender identity are closely aligned in these considerations for Clinton as the first female president. While majorities across all groups say it will not matter, 4 in 10 Democrats and nearly 3 in 10 women say this fact will make them more likely to support her. Among men who see her gender as a factor, 19 percent are more likely to count it in her favor, and 11 percent say it makes them less likely to consider supporting her.

But Republicans who say it is an issue see it as a net negative, with 24 percent saying her gender will make them less likely to support her and 8 percent saying it makes them more likely to support her.

Clinton has been building a campaign-in-waiting and a message tuned to the constrained economic fortunes of the working and middle classes. In speeches over the past several months, she has focused especially on the challenges faced by working women. Unlike in 2008, she is expected to embrace her status as the first nationally viable female presidential candidate.

Clinton’s advantages over Republican hopefuls are greater among both male and female voters in the new poll. Female voters favor Clinton by 20 to 24 points depending on which potential Republican candidate is matched against her, while men split more closely. Romney won male voters by 52 percent to 45 percent over Obama, according to 2012 exit polls. Clinton edges Romney by 50 percent to 46 percent among male voters in the new poll. Her 59 percent to 36 percent lead over Romney among female voters is bigger than Obama’s 55 percent to 44 percent over Romney among women in 2012.

The underpinnings of Clinton’s support in matchups with Republicans are consistent across almost all voting groups for each of the five potential rivals tested in the poll. She wins more than 90 percent support from registered Democrats, whereas her Republican challengers win less than 80 percent among fellow Republicans. Clinton leads each opponent among political independents, a group that narrowly favored Romney over Obama in 2012 even as the Republican lost by four points overall.

White voters tilt toward the Republican candidates, but only by single digits (from three to seven percentage-point margins). Romney and John McCain won whites by 20 and 12 points, respectively, against Obama in 2012 and 2008.

The Post-ABC poll was conducted Jan. 12-15 among a random national sample of 1,003 adults interviewed by telephone, including 311 cellphone-only respondents. The overall margin of error is plus or minus 3.5 percentage points. Of the 1,003 adults interviewed, 843 were registered voters. The margin of error for this subset is plus or minus four percentage points.

Scott Clement contributed to this report.