Washington (CNN) - With every passing month, the campaign to encourage Hillary Clinton to run for president grows.
And supporters at the Ready for Hillary Super PAC say they're turning up the heat.
The group, whose goal is to lay the groundwork for a Clinton campaign in 2016, currently boasts about 2 million supporters – but a Ready for Hillary source hopes that number will swell to roughly 5 million by the end of year.
The early collating and cataloguing of a base of supporters, largely through e-mail, comes after then-Sen. Barack Obama trounced the Clinton campaign’s social media efforts in the race for the 2008 Democratic presidential nomination.
Ready for Hillary is also raising money for the campaign they hope to see.
They are bracing for an expensive campaign cycle, should Clinton choose to run. Craig Smith, a senior adviser for Ready for Hillary, has made an “educated estimate” that a 2016 campaign could cost $1.7 billion including spending by outside groups, the source confirmed.
The numbers were first reported by Time Magazine's Mark Halperin.
Stuart Rothenberg, the editor of the the non-partisan Rothenberg Political Report, said Smith's fundraising figure is both part real and part motivation.
"I can see them picking a figure that is at the outer edge of their estimates because they want to set a goal that is both reachable but also a bit of a stretch," Rothenberg told CNN. "You want your fundraisers to feel like they have to work hard and you want your contributors to feel like they need to reach."
During the 2012 election, Democrats – including outside groups and the Obama campaign – spent around $1.1 billion dollars to win reelection for Obama. Rothenberg said because of the 2012 spending, "you have to assume every campaign can spend at least 1.1 billion, they know how to do it."
"But for most Americans, anytime we get a figure that has a B in it, people's eyes glaze over and they just start shaking their heads," Rothenberg added.
Ready for Hillary raised $4 million in 2013.
Clinton has said she would make a decision about running for the White House by the end of the year.
CNN's Dan Merica contributed to this report