Just over one week ago, US Senator Joe Manchin made headlines when he wrote an open letter to federal regulators calling for an outright ban of bitcoin, and now he has received a tongue-in-cheek response from a fellow politician, Congressman Jared Polis.

The Colorado representative issued a letter today to the same federal regulators that Manchin addressed, and in the letter Polis satirically calls for a ban on the physical US dollar.

Elaborating on his concerns about the dollar, Polis wrote that "the exchange of dollar bills, including high denomination bills, is currently unregulated and has allowed users to participate in illicit activity", mirroring similar statements made by Manchin about bitcoin.

The West Virgina Senator suggested that the digital currency's value to the US economy is "suspect, if not outright detrimental”, and urged federal regulators to ban its use in the States before Americans get left "holding the bag on a valueless currency".

Many opponents of bitcoin argue that its ability to be transacted anonymously lends the digital currency to illicit activity like money laundering. While Polis made no claims against this, he also gave a sound observation that the same properties that make bitcoin susceptible to illicit activities are found in the US national currency.

Wrote Polis:

Notably, one day after Senator Manchin urged regulators to ban bitcoin, Federal Reserve chairwoman Janet Yellen issued her very first statement regarding the digital currency, stating that the Federal Reserve doesn't have the authority to "supervise or regulate bitcoin in any way".

Congressman Polis' request to ban the US dollar is admittedly made in jest, but Polis hopes that his letter to regulators incites meaningful conversation in the US government about regulation of bitcoin and other digital currencies.

Speaking to CoinDesk, Polis said:

"As digital currencies like bitcoin become more popular, the level of awareness will increase in Congress as well.

It's important to continue to establish the basic fact that the dollar is the currency of choice for cartels, criminals and illicit transactions and is likely to stay that way for the forseable future."

As bitcoin continues to gain awareness with the public both in the US and abroad, the issue of governmental regulation is becoming difficult to avoid. Mt. Gox's recent filing for bankruptcy is one example where government regulation arguably could have improved customer protections, and many people in the industry suggest that a regulatory framework may be necessary in bringing digital currencies to mainstream adoption.

Polis said that while he believes digital currencies like bitcoin will continue to gain traction around the world, he doesn't expect them to replace government issued fiat currencies, at least not in the near future:

"I think that digital currencies, whether it is Bitcoin other existing digital currencies, have many advantages over government currencies.

I think there will be an increased role for digital currencies over timem but I doubt that they will replace government issued currencies any time soon."

The future of bitcoin regulation is yet to be seen, but with more politicians like Congressman Polis and Senator Manchin voicing their opinions about the digital currency, it is becoming clear that governments are starting to take the issue more seriously, for better or for worse.