Ever since Taiwan's cabinet approved plans for a special budget to buy $18bn of weapons from the United States, the issue has proved highly controversial.
There have been heated debates over the arms deal and large protests in Taipei and other big cities - including one in the southern port city of Kaohsiung last week end.
Taiwan wants to upgrade its missile defence system
The government had hoped the plan would get swift legislative approval in the current session. Instead, it is shaping up to be one of the hottest topics in legislative elections set for 11 December.
The arms purchase - which includes Patriot Pac-3 antimissile systems, eight diesel submarines and anti-submarine aircraft - is part of a package first approved by Washington three years ago.
The US switched diplomatic recognition from Taiwan to China in 1979. But under the Taiwan Relations Act, Washington is obliged to supply weapons to Taiwan to allow it to maintain a self-defence capability against a possible Chinese attack.
China claims sovereignty over Taiwan and has threatened to take the island by force.
For years, Taiwan had urged the US to sell it more sophisticated military hardware to defend it against mainland China.
Time running out
Defence officials in the US and Taiwan say there is a now a new urgency.
For starters, there is no guarantee that after the US presidential election, Washington will honour the existing arms package on offer.
And some US officials appear to be losing patience with Taiwan.
US Deputy Undersecretary of Defense, Richard Lawless, said this month that the island would be viewed as a liability rather than a partner if lawmakers did not approve the arms package.
Taiwan's Foreign Minister, Mark Chen, is also concerned about the impact on ties with the US if the arms budget is not passed.
"The basic message that could be interpreted by our American friends is that we are not really willing to defend Taiwan by ourselves," he said.
"Our mutual interactions may be discounted in some way; and that's something I don't want to see that happen. "
Analysts worry that the military balance of power is already tipping in China's favour.
China has already targeted more than 600 missiles at Taiwan, and is adding around 75 ballistic missiles each year to its arsenal.
"We are facing China's military threat; therefore have to defend ourselves to increase our defence capability," said Deputy Defence Minister Michael Tsai.
He said the weapons Taiwan wants to buy are of a defensive nature, designed to intercept incoming missiles and aircraft and detect underwater submarine operations.
The Ministry of National Defence (MND) has embarked on an unprecedented public relations campaign to try to convince a sceptical public that the costly arms purchase is essential.
It earlier released brochures with cute cartoon characters setting out its case.
One argument said the money for the weapons deal over the next 15 years was equivalent to the savings that could be made if the people of Taiwan skipped drinking one cup of a popular drink called pearl milk tea each week, over the same period of time.
Last week, the MND opened up one of its three Patriot missiles bases for the first time to the media, to underline its argument about the need for more advanced weaponry.
But critics have questioned the massive cost - and the effectiveness of the systems on offer to deter threats from China.
They say the money would be better spent on public welfare projects.
Many like Hsu Hsin Liang, a founder and former chairman of the governing Democratic Progressive Party who has since moved away from the party, fear Taiwan will end up in an arms race.
There have been big protests against the costly arms deal
"There is no way Taiwan can compete against China in military build-up. This kind of military build-up itself is against peace," he said.
"The more you buy weapons the more dangers we face."
Protestors are now urging people to not vote for legislators who support the arms deal in December's.
"We think Taiwan peace is more important than an arms race," said Professor Yachung Chang, of one of the protest groups, the Democratic Action Alliance.
"More legislators are supporting us - saying if they are re-elected they will back our case."
Out on the campaign trail, Lai Shih Bao, candidate for the opposition KMT, has made it a key plank of his election campaign.
"The arms sale is a hot issue", he said. "We are against this; we don't need this expensive budget. We're not against national defence, but we oppose this special budget."
Political manoeuvring in the legislature has meant that a vote on the arms deal is unlikely to take place before the elections.
The governing DPP and its smaller ally, the Taiwan Solidarity Union, hope to increase the number of seats they hold in the 225-seat legislature and gain a working majority.
In 2001 elections, the DPP captured 87 seats.
But Deputy Defence Minister, Michael Tsai, is cautiously optimistic that the budget will eventually be passed. The bill is high, he admitted, but unavoidable.
"What a choice do we have? The US spends a lot; so does Japan, Israel, so does Singapore. I know its more expensive to develop defensive than offensive weapons. But in order to win the peace, we have to pay the price," he said.