(CNN) Hillary Clinton hasn't hit the campaign trail yet on behalf of Democrats running in 2018, but that isn't stopping Republicans from using the former 2016 Democratic presidential nominee as a reliable campaign boogeyman.

In Pennsylvania's special election earlier this month, a super PAC aligned with House Speaker Paul Ryan handed out door-hangers that featured Clinton and Nancy Pelosi to attack Democrat Conor Lamb.

And over the past two weeks, Republicans have tried to tie vulnerable Democratic senators to comments Clinton made at a recent event in India that were seen as a knock at more conservative areas of the country, in which she said she "won the places that are optimistic, diverse, dynamic, moving forward." President Donald Trump, she said, ran a backward-looking campaign.

The National Republican Senatorial Committee has cut digital ads featuring Clinton's comments that target 10 Democratic senators running for reelection in states Trump won in 2016. The Republican challenger to one of those Democrats, Missouri Sen. Claire McCaskill, has also released digital ads tying McCaskill to Clinton and her comments.

Clinton later explained in a Facebook post that she "meant no disrespect to any individual or group," but the political distancing and downright rebuking of her comments from red state Democrats came swiftly.

"It wasn't helpful. I thought it was wrong how she put it," McCaskill told MSNBC in an interview last weekend.

"For those of us that are in states that Trump won," McCaskill added, "we would really appreciate if she would be more careful and show respect to every American voter and not just the ones who voted for her."

When asked in a radio interview when she thought Clinton would exit the political landscape, North Dakota Sen. Heidi Heitkamp said, "Not soon enough."

Democrats, especially those running in tough races in areas of the US that Trump won, aren't necessarily eager to have Clinton as a surrogate.

Sen. Bill Nelson from Florida, in an exchange with the Tampa Bay Times this week, declined to answer whether he would campaign with Clinton as he seeks re-election this year.

"Obviously when she was a candidate, I campaigned with her. That's like you asking me would I campaign with Robert Redford. ... We'll take that up when we get there," he said.

One Democratic strategist working on a competitive 2018 Senate race said he'd rather have Trump visit the state for his candidate's Republican opponent than Clinton visit to support his candidate.

The strategist's thinking: Clinton has never been a major draw at public events, so there's limited upside. Trump, though, has embarrassed those he's campaigned with -- particularly Alabama Republican Luther Strange -- by veering far off-topic and seemingly all but forgetting that the candidate is also on stage. Local coverage of a bombastic and unpopular President and footage of the two sharing the stage could actually help a Democratic candidate, this strategist argued.

Even in the 23 Republican-held House seats that Clinton won in 2016, where she would arguably the most helpful, several other Democratic strategists said she's not the most in-demand Democratic surrogate. Candidates, those strategists said, first ask for the Obamas -- Michelle, and then Barack.

And former Vice President Joe Biden has effectively replaced Bill Clinton in the role of a Democrat who can campaign effectively in deep-red regions such as Alabama, where he boosted Doug Jones in December's Senate special election, and Pennsylvania, where he backed Lamb.

Clinton hasn't yet scheduled any appearances for individual candidates in 2018. She'll wait until closer to this summer to wade through the requests for appearances and fundraisers from candidates and Democratic groups, spokesman Nick Merrill said.

Rather than play the role of campaign surrogate, aides say Clinton has carved out a position as a seed investor and strategic adviser of the anti-Trump resistance.

On the advice of Howard Dean, the former Vermont governor and Democratic National Committee chairman, she launched Onward Together, an organization with non-profit and political action committee arms, as the hub of her post-election activity.

It's designed to serve as an accelerator of sorts, injecting money and expertise into the new progressive groups that have proliferated since Trump's election while also signaling to major donors that those groups have Clinton's stamp of approval.

Former campaign staffers Emmy Ruiz, Adam Parkhomenko and Nick Merrill are involved in the effort, as well as Dean and Clinton herself.

In 2017, the group injected about $1 million into groups like Swing Left and Run for Something, all launched since Trump's election.

Clinton also made those staffers available as consultants for the organizations she backed.

That, Merrill said, means anything from assisting with digital efforts to op-eds and fundraising.

The main political event now on Clinton's calendar, Merrill said, is a late-April gathering in New York of the Democratic groups that her political organization is backing. It's being planned as days' worth of working groups and introductions to donors, with Clinton playing a central role.

Those progressive groups credit Clinton's organization with helping them through their fraught early months.

"They've been amazing. We wouldn't have made it through the first year without their help," said Amanda Litman, the former Clinton campaign email director who became the co-founder of Run for Something, which helps young Democrats to run for office for the first time.

She said a six-figure contribution from Clinton's Onward Together came with no strings attached last year, allowing the group to quickly spend a "huge chunk" of it in Virginia state legislative races, "directly to candidates or funding canvasses or advertising."

The behind-the-scenes maneuverings fit Clinton well, Litman said, particularly because she's aware the 2018 battleground map, especially in the Senate, features competitive races in a number of states where she was trounced in 2016.

"If a candidate or an org thinks something wouldn't be helpful," Litman said, "she's not going to do it just because of her ego or to be able to say 'I helped.' She is not un-self aware about what implications her role has."