NBC News:

When allies of former President Barack Obama set up a super PAC to support his 2012 re-election, the White House disowned the group, The New York Times published a scathing editorial and former Democratic Sen. Russ Feingold of Wisconsin gave a speech warning Democrats would “lose our soul” if they allowed big money into the party.

But fears of being outgunned trumped those principled objections and, less than a decade later, Democratic super PACs are spending more than Republican ones. Liberal “dark money” groups, which obscure the source of their funds, outspent conservative ones for the first time in 2018. Even reform hawks like Elizabeth Warren and Bernie Sanders had their own personal big-money groups supporting their presidential campaigns.

“Their mantra of not ‘unilaterally disarming’ was really their justification for learning how to master super PACs and dark money and all that, and they’re doing a better job of it right now than the Republicans,” said Craig Holman, a lobbyist for the good-government group Public Citizen.

Advocates are concerned with super PACs, which can accept donations of unlimited size but have to reveal the names of their donors and regularly disclose their activity. But they’re more worried about dark money groups: nonprofit organizations that can’t be as explicitly political as super PACs, but can keep their donors secret forever and don’t have to reveal much about activities before elections.

While concerns about campaign finance reform that once animated Democratic voters have been eclipsed by the desire to oust President Donald Trump, advocates are left to wonder if the party can really be trusted to follow through on its promises to dismantle a system that may help them get elected.

“If Democrats were to win the Senate and the White House, there is reason to be concerned that they may not carry through with their commitments,” Holman added. “I have no doubt that we are going to have to hold their word over their head.”…

In 2016, conservative dark money dwarfed liberal dark money nearly 4-to-1: $143.7 million to $37.8 million. But two years later, in the 2018 midterms, the backlash against Trump helped liberal dark money groups outspend their counterparts for the first time, according to an analysis by Issue One, a bipartisan political reform organization. And they’re on track to potentially do it again this year.

It’s impossible to comprehensively track dark money spending in real-time, which is one of the most controversial parts about it. But the limited picture that has emerged so far in 2020 shows $14.2 million in dark money has been spent supporting Democrats or against Republicans versus $9.8 million to support Republicans or attack Democrats, according to Open Secrets.

“Campaign spending is frequently like an arms race. Once one side develops a new weapon, both sides want to have it in their arsenal,” said Michael Beckel, research director for Issue One.