NEW YORK - The 2016 presidential election will be a difficult fight for Hillary Rodham Clinton or any Democrat, and Republicans are likely to capitalize on voters' desire for change after eight years of a Democratic president, potential advisers and supporters of a Clinton candidacy said Friday.

"A tough thematic will be, 'a time for change,' and you can shove a lot under that thematic," said longtime Clinton adviser Harold Ickes.

Speaking to reporters after he briefing potential donors and organizers for a Clinton candidacy, Ickes said he told the group to prepare for a difficult election with a national electorate that remains roughly split 50-50 between the parties.

"If they put up the right ticket - and they’ve been known not to - but if they put up the right ticket, it could come down to be very, very hotly contested," Ickes said he told the meeting of leading donors to Ready for Hillary, a pro-Clinton super PAC.

The group held a day-long session that featured briefings for donors by Clinton figures past and present with the expectation that Clinton will soon announce her candidacy. Many of the Ready for Hillary speakers preached the gospel of early organization and sophisticated voter databases - or as Ickes put it, "the list, the list, the list, the list, the list."

"Inevitability is not a message, it’s not something you can run on," added Terry Shumaker, a longtime Democratic  organizer in New Hampshire.

Clinton will need to quickly articulate why she is running, and distinguish herself from both her past and the last eight years, several participants in the Ready for Hillary session said.

"If she decides to run, she should not run as the third Bill Clinton term or a third Barack Obama term. She should run as a first Hillary Clinton term," said Craig Smith, a veteran Clinton strategist who has been advising Ready for Hillary.

Stephanie Schriock, president of the women's candidate network Emily's List, echoed the challenge of a Democratic candidate running to succeed a two-term Democratic president. She also said Clinton faces a special challenge as a universally known quantity and prohibitive front-runner.

"History says Americans really don't like to go with the same party for three terms," Schriock told reporters following her presentation to the donor group. "It's going to be the candidate who makes the case, and she's going to have to make the case."

Ready for Hillary has amassed a list of roughly 3 million supporters and raised nearly $11 million - including many contributions of $20.16 - in hopes of encouraging Clinton to run.

The database was a main goal of the organization, and much of the infrastructure Ready for Hillary built could fold into an official Clinton campaign once she announces and Ready for Hillary folds its tent, Ickes said.

Planned obsolescence was always the strategy behind Ready for Hillary, and the New York donorfest Friday served as something a valedictory for an organization that founders said far surpassed their original goals.

Under federal election rules, super PACs cannot directly coordinate certain kinds of fundraising and other activities with candidates, but Ready for Hillary is planning a legal way to make its list available to a Clinton 2016 campaign.

"If she decides to run she will have the ability to access that list," as part of a critical early database of potential supporters, Ickes said. The lesson of Barack Obama's 2008 and 2012 campaigns "underscored the importance of data, modeling, and the ability to identify and connect with individual voters."

Ready for Hillary will keep running for now, co-founder Adam Parkhomenko said. The group has 21 stops planned for its touring bus over the coming weeks, and is running what is likely to be a final organizing push for more names and supporters.

Ickes and others said they do not know whether Clinton will indeed mount a second run for the White House, or when she might announce. Schriock would not address rumors that she is a candidate to run the unannounced Clinton campaign.