They have been ignored for their small numbers or simply seen as window dressing in the past, but this year, Asian-Americans in key battleground states are finding themselves being courted by both Hillary Clinton and Donald Trump's presidential campaigns, who believe the rapidly growing group could play a decisive role in a photo finish.

The Asian-American community is the fastest growing demographic group in the United States with its population almost doubling between 2000 and 2010 in key swing states such as Nevada and North Carolina, where they now constitute a voting bloc big enough to eclipse the margin between the two candidates in pre-election polls.

"Asian-Americans are poised to be the margin of victory in a battleground state. This is not just an abstract possibility. We have seen it before," said Taeku Lee, professor of political science and law at the University of California, Berkeley.

Lee cites the example of the 2014 Virginia Senate race between the Democrat Mark Warner and his Republican opponent Ed Gillespie. Senator Warner managed to scrape through with a margin of about 20,000 votes.

"That margin is well within the difference between Asian-Americans who voted Democratic and those who voted Republican in the Virginia Senate race. In short, if Asian-Americans sat out that race, Ed Gillespie would have won," said Lee.

Clinton's Asian outreach

The Clinton campaign understands the importance of the community, which has tended to lean Democrat in the past two decades. It has launched an Asian outreach effort to ensure Asian-Americans stick by it in November elections.

Campaigners aim to reach voters in whichever language they prefer

The undertaking includes reaching out to eligible voters from the community through advertisements in Asian languages such as Urdu, Vietnamese, Hindi and Korean. The Democratic Party volunteers are also making phone calls in a handful of Asian languages to broaden contact within the diverse group, a third of which doesn't speak fluent English.

"The effort with the campaign was how to get information out to people in whatever form they wanted, in whichever language they wished to see it, they should be able to experience it," said Shekar Narasimhan, chairman and founder of Asian-American and Pacific Islanders (AAPI) Victory Fund.

"Let them decide cognitively and not reflexively … This is another way to say I care about your vote."

Narasimhan's AAPI Victory Fund is a super PAC exclusively focused on the Asian-American community. Super PACs are public action committees aimed at raising funds to advocate for or against political candidates.

These are busy times for Indian-American Narasimhan, juggling between his primary job of helping companies and investors make sound financial decisions and his passion for raising the level of civic engagement within the community. His Victory Fund is targeting those swing states where the number of Asian-Americans eligible to vote this year exceeds the margin of difference between the candidates in the 2012 presidential election.

Narasimhan, a Democratic Party supporter, knows that a good turnout of Asian-American voters could ease Hillary Clinton's path to the White House. The community overwhelmingly supported President Barack Obama's bid to retain the presidency, with nearly three in four Asian-American voters casting ballots for the incumbent. That ratio is expected to remain the same on election day in November, according to current polls.

Getting Asians to register and vote

But Narasimhan, an alumnus of the prestigious Indian Institute of Technology (IIT) in Delhi, has a challenge at hand.

Asian-Americans are not known to be keen voters. Just a little over half of those eligible registered to vote in 2012, significantly lower than the more than 70 percent of eligible black and white voters who registered.

Experts say low registrations are mainly due to the fact that Asian voters have not been wooed by either party at rates that are comparable to other racial groups. There is also a sense among the community that it's too small to make any significant difference.

The big challenge for Narasimhan is finding a way to motivate voters

AAPI Victory Fund plans to change that perception. It has been organizing events targeted at Asian-Americans, educating them about the importance of voting.

"I feel it's our responsibility in a democracy to ensure that everybody has the opportunity to register and vote and be educated on the issues," said Narasimhan, who is the grandson of a prominent Indian freedom fighter and journalist.

"How do I mobilize my community, particularly young people who do not have a connection with their motherland or fatherland, and make them realize the importance of civic engagement?"

The Republican effort

The Republican Party is also seeking to register new Asian-American voters in a bid to make inroads into the Democrats' support base. In September, the Trump campaign set up an advisory body to "engage Asian-Americans and Pacific Islanders on relevant issues."

Earlier in the month, Donald Trump attended a charity event organized by the Republican Hindu Coalition.

"I am a big fan of Hindu and I am a big fan of India. Big, big fan," Trump said at the fundraiser. He added that if he's elected, the Indian and Hindu communities will have "a true friend" in the White House.

But the Trump campaign has the unenviable task of playing down the presidential nominee's hard-line anti-immigrant rhetoric. Even though he has not focused on Asian-Americans, his comments have still managed to drive away many Asians from the Republican Party.

"They have shifted further and further to become a party of exclusion. And Donald Trump is the latest evidence of that. He is not the only evidence," said Narasimhan. "If you don't want me why should I want you?"