The attacks and fund-raising appeals started early this year and haven’t stopped.

Buoyed by Michigan’s turn from blue to red in the 2016 presidential race, Republicans have placed a target squarely on the back of U.S. Sen. Debbie Stabenow, who is up for re-election in 2018.

Earlier this month, the National Republican Senate Campaign Committee ran advertising pointing out that Democrat Stabenow had criticized Republicans for ignoring President Barack Obama’s Supreme Court nominee, Judge Merrick Garland, but wouldn’t promise a vote for President Donald Trump’s nominee, Judge Neil Gorsuch.

In January, the 45 Committee, a conservative super PAC that spent $21.3 million in 2016 to attack mostly Democratic candidates, paid for nearly $100,000 in TV advertising on network stations in Michigan to give voters phone numbers where they could call their Democratic senators — Stabenow and Gary Peters — and urge them to support Trump's cabinet nominees.

The Michigan Republican Party, Republican National Committee and American Rising PAC, another conservative political action committee formed to do opposition research against Democrats also have been piling on with frequent e-mail attacks and fund-raising appeals to oust Stabenow for a more conservative Michigander in the U.S. Senate.

But without a named candidate to go up against the formidable Stabenow, a former state representative and senator and U.S. representative who knocked off the last Republican senator from the Great Lakes state – Spencer Abraham — in 2000, the battle lines are still a bit fuzzy.

Republicans would love to see a big-name candidate jump into the race — think former Michigan Secretary of State and U.S. Representative and current Macomb Public Works Commissioner Candice Miller or former Michigan Gov. John Engler — and preferably one that can bring some of their own wealth to a campaign that easily could top $20 million.

“But Candice left Washington for a reason,” said Tom Shields, a political consultant and president of Marketing Resource Group in Lansing. “And Engler’s name has been floated, but I just don’t think that’s where he’s at.”

Engler said he thinks Michigan is ready for a new U.S. senator, “but it’s not going to be me,” adding he’s newly retired from the Business Roundtable, an association of CEOs of leading U.S. companies who promote sound public policy that leads to a thriving economy, and is anxious to watch his triplet daughters graduate from college this spring.

Other Republican names are popping up such as U.S. Reps. Fred Upton of St. Joseph and Justin Amash of Cascade Township, former U.S. Rep. Mike Rogers of Brighton, former state Senate Majority Leader Randy Richardville of Monroe, or the unlikely duo of musicians Kid Rock and Ted Nugent, who posted a profane promise on his Facebook page about the Senate race: “If these GOP sonsabitches dont get it right this time I will come charging in as the ultimate WE THE PISSED OFF PEOPLE Mr FixIt Consitutional firebreathing sh!!kicker candidate from hell!”

Richardville, who left the state Senate in 2014 because of term limits, said he’ll make a decision on the race by this summer. He talked with Nugent last week, noting, “I would say I’m passionate about music, but don’t put me on stage. I would love to have their support.”

With Michigan going for Trump in November and Stabenow a staunch and visible supporter of Democrat Hillary Clinton in 2016, Richardville said an opportunity like this doesn’t come around very often. And besides, Michigan has an advantage with the new leaders of the Republican National Committee and Michigan Republican Party.

“Ronna Romney McDaniel is now in arguably the most important political position in the country. Ron Weiser may be the best fund-raiser that the Republicans have had ever,” Richardville said, referring to the new heads of the RNC and Michigan GOP. “And Donald Trump won Michigan. He likes loyalty and he likes giving back to people who supported him.”

The two Republican leaders will help with fund-raising for a GOP candidate, Shields said, but there are a lot of other open races in 2018, including governor, attorney general, secretary of state and all the state House and Senate seats.

“There is a lot of competition for those dollars in this cycle,” he said. “But Weiser has the contacts and the ability to raise money in the state. I think he can add in the Senate campaign. You’re limited what you can raise locally for the Senate raise, so the money really has to flow through the national parties.”

But no Republican underestimates Stabenow’s ability to raise money, campaign and work with constituents.

“Debbie Stabenow is a difficult candidate to beat. She’s deeply tied to the Farm Bureau and the agriculture communities,” said Matt Marsden, a Republican political consultant based in Oakland County, noting Stabenow shepherded the 2014 Farm Bill, which governed all aspects of federal regulation over agriculture while she was chairwoman of the U.S. House Agriculture Committee. “But until we know who the Republican candidate is going to be, it’s difficult to handicap. It’s going to be an uphill fight for the Republicans.”

She has a substantial war chest already with $3.2 million from more than 2,500 contributors on hand to start a campaign, as well as nearly $600,000 in her “Victory Fund.”

“It’s going to be a competitive race, but I think it’s way too early to imagine what it’s going to be like in 2018,” Engler said. “But there will be an opportunity for a Republican candidate who is reasonably well-funded.”

He noted that Stabenow and other Democrats in Washington are taking “a flat-out opposition to President Trump whether it’s good for the home state economy or not. And they’re going to have to live with that.”

But Democrats know they can count on Stabenow to continue to criss-cross the state, meeting with Michiganders and helping constituents no matter who they voted for.

She hasn't done too much overt campaigning yet, noting almost as an afterthought during a fiery speech at the Democratic Party's spring convention earlier this month, "I'll be on the ballot, by the way," but she is sending out frequent fundraising appeals.

“From a Democratic perspective, Debbie Stabenow is doing a great job. Even between elections, she’s out and about all over the state,” said former state Democratic Party Chairman Mark Brewer. “I was talking with a Republican last week who was telling me how Debbie is going to bat for him with the Veterans Administration.

“We’ll just have to see who Republicans come up with. She’s a terrific candidate and a very strong incumbent.”

Brandon Dillon, the current party chairman, said the agriculture community, especially, will help with Stabenow’s re-election efforts. Usually Republican-leaning, the Michigan Farm Bureau endorsed her over her last Republican challenger, former U.S. Rep. Peter Hoekstra of Holland, whom she beat with 59% of the vote. She dispatched her 2006 rival — Oakland County Sheriff Michael Bouchard — with 57% of the vote.

But the 2016 election has Democrats rethinking their message and approach to upcoming campaigns.

"Last year certainly demonstrated that Michigan is a competitive state," Dillon said. "She has won re-election twice now and she knows this state, but she still has to appeal to Democrats, independents and some Republicans as well."

â–ºMake it easy to keep up to date with more stories like this. Download the WZZM 13 app now.

Contact Kathleen Gray: 313-223-4430, kgray99@freepress.com or on Twitter @michpoligal

U.S. Sen. Debbie Stabenow

Age: 66

Hometown: Lansing

Political experience: U.S. Senate, 2001-present; U.S. House of Representatives, 1997-2001; state Senate, 1991-1994; state House, 1979-1991.

Education: Bachelor's and master's in social work from Michigan State University

Personal: Divorced, two children.