Last month I wrote about Sanders’ chances and cited money as a key advantage for Clinton in the race. How times have changed.

Clinton raised $40 million more than Sanders in 2015, but spent a lot of it and ended the year with only $10 million more cash-on-hand than the Vermont Senator. In January, Sanders raised $5 million more than Clinton, leaving her presumably ahead by around $5 million.

Then Sanders turned his victory speech in New Hampshire into an impromptu crowdfunder.

I'm going to hold a fundraiser right here, right now, across America. My request is please go to BernieSanders.com and contribute. Please help us raise the funds we need, whether it's 10 bucks, 20 bucks, or 50 bucks. Help us raise the money we need to take the fight to Nevada, South Carolina and the states on Super Tuesday.

We don’t know exactly how much the campaigns have raised this month to date, but if Clinton had a lead of $5 million coming into the February and Sanders raised $7 million in a single day it’s fair to wonder if he’s already passed the former secretary of state in cash-on-hand.

Clinton can still turn to exclusive fundraisers with the one per cent, or activate her SuperPAC to do more heavy lifting for her campaign, but both courses of action reinforce the Sanders narrative of her campaign as serving financial elites and could backfire. This is the genius of the Sanders communications and fundraising operation: Every dollar Clinton raises on Wall Street just makes it easier for Sanders to raise cash from Main Street.

Meanwhile the size of the Sanders campaign’s average donation ($27, as the candidate is fond of repeating, now up to $34) means they’ve captured over a million voters who can keep donating throughout this campaign without violating the donation limit. For a political campaign, that’s a little bit like a licence to print money.

If Sanders hasn’t passed Clinton in cash-on-hand already, he will soon. Once he does, it’s a lead he’s unlikely to relinquish. That’s a reality that seemed inconceivable only a month ago.

Momentum matters in politics, and right now Sanders has it. Whether he can retain it through Nevada and South Carolina is the open question.