Cryptocurrencies should be written into the Japan-U.S. trade agreement that was signed in 2019, two experts from a prominent think tank said.

In a blog post on Wednesday, Rand Corporation senior policy analyst Sale Lilly and senior political scientist Scott Harold said the deal was a missed opportunity for the crypto industry.

"Given that some of the earliest cryptocurrency markets began in Japan, and that many of the largest companies originate in the U.S., this decision was somewhat surprising," the pair wrote.

The 2019 agreement was a "landmark" document touching on a number of topics that hadn't been included in previous international trade discussions.

Digital representations of a photo, movie or song as well as trading an algorithm are now components of bilateral trade covered by the agreement, which prevents new tariffs between the two countries.

With the beginnings of new political regimes in Washington and Tokyo, it may be time to reconsider the exclusion of crypto in the deal, Lilly and Harold wrote.

The deal, which was inked during Donald Trump's presidency and ahead of other major international digital trade agreements, is "especially prescient" given it came right before the outbreak of COVID-19, the pair said.

Still, there is no mention of crypto and only some aspects of blockchain may land under the purview of the tariff-free structure.

"The reality ... is that blockchain systems are often deployed alongside better-established networks, like Ethereum or Cardano, that do employ tokens and digital currency," they said.

Concerns arise from the potential to retroactively tack tariffs onto budding blockchain and crypto businesses as long as cryptos remain excluded from the agreement.

To rectify that, Lilly and Harold said the U.S. and Japan could formulate a new agreement covering crypto and digital assets or else reinterpret the terms of the 2019 agreement.

Rand's approach and analysis of cryptos have changed significantly in recent years given the development of the digital currencies and regulations. In 2015, the think tank released a 100-page report that focused on scenarios in which entities in conflict zones could seek to use a digital currency for nefarious means.

"A clear, jointly negotiated U.S.-Japan agreement toward regulating the use of cryptocurrencies in international trade may be an idea whose time has come," Lilly and Harold wrote.