Half of Americans express a favorable view of the 2014 Winter Olympic Games - plenty for a broad audience but far fewer than greeted the 2012 summer games in London. A range of factors may be at play, among them, dim views of the Russian president, Vladimir Putin.

Fifty percent in this ABC News/Washington Post poll hold a favorable opinion of the Winter Olympics starting this week in Sochi, Russia, while 40 percent see the games unfavorably. That compares with a 72-16 percent rating for the London games ahead of their start in July 2012.

See PDF with full results and charts here.

Generally higher popularity of summer sports may be one factor. Security concerns may be another; 53 percent express a favorable opinion of Russia's anti-terrorism preparations for the games, a majority but not a particularly robust one. And there's the influence of Putin himself, seen favorably by just 27 percent of Americans, unfavorably by more than twice as many.

Indeed, "strongly" negative opinions of the Russian president outnumber strongly positive ones by 5-1 in this poll, produced for ABC by Langer Research Associates. And views of Putin are closely related to perceptions of the games overall: Among the roughly quarter of Americans who see Putin favorably, 71 percent also see the Sochi games positively and 79 percent rate Russia's anti-terrorism efforts favorably. Those plummet to 43 percent, in both cases, among the majority that sees Putin negatively.

Other factors may be influencing attitudes toward these Olympics. Those include coverage of the high cost of staging the games, allegations of corruption in contracting, criticism of Russia's restrictions on gay rights and perhaps annoyance about its granting asylum to Edward Snowden, the former National Security Agency contractor charged with disclosing U.S. surveillance secrets. In a Gallup poll last fall, 64 percent disapproved of Russia's handling of the Snowden affair.

Another, more general factor may be lingering distrust after the Cold War and continued tensions in U.S.-Russian relations since. That's a contrast with London, given long-term, highly positive views of the United Kingdom and a strong U.S.-U.K. alliance.

GROUPS - With minorities less apt to participate in Winter Olympic sports, the games are seen more favorably by whites than nonwhites, 54 vs. 44 percent. That makes the Sochi games less popular than the London Olympics by 29 percentage points among nonwhites, vs. 19 points among whites.

Possibly reflecting criticism of Russia on gay rights, positive views of the Sochi games also bottom out at 44 percent among liberals, 37 points off the popularity of the 2012 games in this group. That compares with a 15-point gap among political moderates and 20 points among conservatives in Sochi-vs.-London favorability.

There's little variation in attitudes on Russia's efforts to prevent a terrorist attack. But some groups are notably critical of Putin personally, including college graduates, higher-income Americans and blacks. These groups also are among those showing steep drops in favorability toward the Sochi games vs. their views of the 2012 Olympics.

Despite their lackluster attraction compared with London, a 50 percent favorability rating is plenty to draw significant audiences - particularly when it comes to the must-see viewing ahead, not least the Norwegian curling team in its full regalia.

METHODOLOGY - This ABC News/Washington Post poll was conducted by landline and cell phone Jan. 29-Feb. 2, 2014, in English and Spanish, among a random national sample of 1,013 adults. Results have a margin of sampling error of 3.5 points. The survey was produced for ABC News by Langer Research Associates of New York, N.Y.