| This is Election Countdown, The Hill's weekly newsletter from Lisa Hagen (@LA_Hagen) and Max Greenwood (@KMaxGreenwood) that brings you the biggest stories on the campaign trail. We'd love to hear from you, so feel free to reach out to Lisa at LHagen@thehill.com and Max at MGreenwood@thehill.com. with any questions, comments, criticisms or food recommendations (mostly the latter, please). Click here to sign up for the newsletter. We're 97 days until the 2018 midterm elections and 825 days until the 2020 elections. President Trump has been selective about candidate endorsements -- factoring in where he can have the most impact, while avoiding being tied to an embarrassing loss. That dynamics is at work again ahead of Tennessee's primaries on Thursday. The gubernatorial primary to replace term-limited Republican Gov. Bill Haslam is the race to watch and one in which the president is notably staying neutral. GOP Rep. Diane Black is battling it out in a tough primary against several Republican rivals, including businessmen Bill Lee and Randy Boyd. Vice President Mike Pence endorsed Black and Trump has previously praised her for helping pass tax reform during her stint as chair of the House Budget Committee. But having Trump officially on your side--and delivering a coveted endorsement in GOP primaries--would have given Black more of a cushion going into Thursday's primary. Trump, though, has weighed in on the race in Tennessee's 8th district where freshman GOP Rep. David Kustoff faces a stiff primary challenge from George Flinn, a radiologist and perennial candidate. Flinn, who's been self-funding his campaign, has heavily outspent Kustoff. Other races to keep an eye on in Tennessee are two open House seats held by Republicans. Trump won both these districts by at least 35 points, and they're expected to remain red in November. In retiring Rep. John Duncan Jr.'s district, seven Republicans are competing for the east Tennessee seat. The mayor of Knox County and a state legislator appear to be the leading candidates, but the only woman in the race, military pilot Ashley Nickloes, is looking to break through the crowded field. And in the race for Diane Black's seat, five Republicans are running including former state Agriculture Commissioner John Rose, who's deeply connected in the district and the leading fundraiser. The president won the 6th district by nearly 50 points, and candidates are touting their support for Trump. The Senate race doesn't have a competitive primary, but it officially sets up the high-profile race between GOP Rep. Marsha Blackburn and former Tennessee Gov. Phil Bredesen (D). Democrats haven't won a Senate race in Tennessee in nearly 30 years, but Bredesen, a popular governor who served from 2003 to 2011, has led in some polls this year. A day before the primary, Blackburn launched her first TV ad of the campaign that focuses on her "strong Tennessee values." Bredesen has also been on the air. Democrats' Senate Majority PAC has indicated that it believes it's worth investing in the Tennessee race and has made reservations for August and fall TV ads. Special election primer We're less than a week out from Ohio's special election and things are heating up quickly as Republicans scramble to hold on to a reliably red seat, where Trump won by 11 points in 2016. Republican Troy Balderson appeared to have the edge for months over Democrat Danny O'Connor, but a new Monmouth University poll out Wednesday -- the first public poll since June -- has the race as a toss-up. The poll comes on the heels of news that Trump will hold a rally Saturday night in the Columbus suburbs to help Balderson. Trump's visit could give him a boost among the base, whose voters are critical in low-turnout races like special elections. A lot can happen over the next six days and the race is clearly still wide open, but Democrats are likely feeling pretty good about their current position. If they pull off an upset victory, it'll give them the narrative they've been looking for: that Democrats can compete in GOP-leaning suburban districts that will be key to taking back the House. Senate showdown Trump is back on the campaign trail, stumping for Florida Republicans in tough election fights. At Tuesday night's Tampa rally, Trump said that "we have to make sure that [Gov.] Rick Scott wins and wins big" in his race to unseat Sen. Bill Nelson (D-Fla.). Scott was notably absent from the rally, but did attend a workforce training event alongside Trump earlier that day. Trump also touted Rep. Ron DeSantis (R-Fla.), an unabashed Trump supporter who attended the rally, who is running in the GOP primary for governor. DeSantis made his loyalty to Trump very clear in a new ad on Monday where he teaches his children how to "build the wall" with toy bricks. The Koch network, the web of conservative groups funded by billionaire industrialist Charles Koch, is giving the cold shoulder to Rep. Kevin Cramer (R-N.D.) in his bid to unseat Sen. Heidi Heitkamp, The Hill's Jonathan Easley reports from Colorado Springs, Colo. In fact for now, the network will only back a handful of GOP Senate candidates in Florida, Wisconsin, Missouri and Tennessee in the midterms as it seeks to freeze out Republicans it believes flouted its brand of fiscal conservatism. In an interview, Charles Koch acknowledged that he regretted backing certain candidates in the past. "We're gonna more directly deal with that and hold people accountable," he said. Former House Speaker Newt Gingrich has made endorsements in the Arizona and Wisconsin Senate races. Gingrich is backing Rep. Martha McSally in the race to replace Sen. Jeff Flake (R-Ariz.), and state Sen. Leah Vukmir in the race against Sen. Tammy Baldwin (D-Wis.). Survey says... Dead heat in Texas and Nevada Senate races: In Nevada, Rep. Jacky Rosen (D-Nev.) and Sen. Dean Heller (R-Nev.) are essentially tied, 41 to 40 percent, in a new poll from Suffolk University and the Reno Gazette-Journal. Meanwhile, in Texas, Rep. Beto O'Rourke (D-Texas) is neck and neck with Sen. Ted Cruz (R-Texas), 41 to 39 percent, in a new Texas Lyceum Poll. But another poll out Wednesday from Quinnipiac University found Cruz ahead by 6 points. Florida's Senate race is also pretty close: A new Mason-Dixon poll shows Gov. Rick Scott (R) leading Sen. Bill Nelson (D) by 3 points, 47 to 44 percent. The poll is within the margin of error, but it's good news for Scott, who previously trailed Nelson. In a new poll from OH Predictive Insights, McSally is the front-runner in the Aug. 28 GOP primary, leading former state Sen. Kelli Ward by 8 points. But McSally still trails Rep. Kyrsten Sinema (D-Ariz.) by 4 points in a hypothetical general election match-up. Three new NBC/Marist polls out last week bode poorly for Republicans in three potential battleground states. The survey shows Trump's approval dwindling in Wisconsin, Michigan and Minnesota. In Wisconsin, one of the state's Trump flipped in 2016, 61 percent of registered voters said they want to "give a new person a chance" in the governor's mansion. That's a bad sign for Gov. Scott Walker (R), who's seeking a third term in office. Sen. Tammy Baldwin (D) is also leading her two possible Republican challengers by at least 15 points, the NBC/Marist poll found. What we're watching for Primary season is back, starting with the Tennessee primaries tomorrow. The next ones will be held Aug. 7 in Kansas, Michigan, Missouri and Washington. That is also the date for Ohio's special election. Trump will continue hitting the campaign trail, with his next rallies taking him to Wilkes-Barre, Pa. on Thursday to stump for Rep. Lou Barletta, who's running for Senate, and Delaware, Ohio on Saturday to campaign for Balderson in the special election Coming to a TV near you The Democratic Congressional Campaign Committee's third wave of fall TV ad reservations total $7.1 million, with much of that going to Dems' battle for seven GOP-held seats that Hillary Clinton won in California. The Hill's Reid Wilson reported from Los Angeles that nearly half of that money -- $3.1 million to be exact -- will be spent in Los Angeles for the seats held by GOP Reps. Mimi Walters, Steve Knight, Dana Rohrabacher and the seat being vacated by Ed Royce. Rep. Kevin Cramer (R-N.D.) is pushing back against an ad by VoteVets, a liberal veterans group, with a spot of his own. A quick refresher on the VoteVets ad: It quotes Cramer saying that increasing defense spending was "becoming a very difficult pill." It accuses him of turning "his back on our veterans and service members." The Cramer remarks were made to Reuters in March also called defense spending a "very high priority" and his criticism seemed to be directed at GOP leaders' handling of a massive spending bill. Cramer's response features a group of military veterans sitting around a table. "I like Heidi. Who doesn't like Heidi? But I don't like the way she votes in Washington," one woman, identified as a retired lieutenant colonel, says, about Sen. Heidi Heitkamp (D-N.D.). The Club for Growth unveiled a new ad spot on Monday resurrecting decades-old unproved domestic violence allegations against Sen. Claire McCaskill's (D-Mo.) husband, Joseph Shepard. The ad also questions whether the senator, who's seeking a third term in office, can be an effective advocate for victims of domestic abuse. The controversial ad drew a firm rebuke from McCaskill's campaign, which denounced it as "an ugly and shameful personal attack." "Claire will not be discussing her husband's divorce, which occurred over 20 years ago," Meira Bernstein, the communications director for McCaskill's campaign, said. "Missourians deserve so much better." Wave watch Two Democrats locked in Indiana House races are among the latest candidates to say that they won't back Minority Leader Nancy Pelosi (D-Calif.) for a leadership role if they're elected: Mel Hall, who is hoping to unseat Rep. Jackie Walorski (R) in Indiana's 2nd district, and Liz Watson, who's looking to oust freshman Rep. Trey Hollingsworth (R) in Indiana's 9th district. Democrats' chances of flipping Rep. Dennis Ross's (R-Fla.) seat may have just gotten a little better. The Cook Political Report moved Florida's 15th district from "likely Republican" to "leans Republican." Ross announced in April that he would not seek reelection in November. Five Republicans and three Democrats are vying for their parties' nominations to replace Ross. Rep. Dana Rohrabacher (R-Calif.), who is in the midst of a competitive race with Democrat Harley Rouda, this week defended the 2016 meeting between Trump campaign officials and a Russian lawyer promising dirt on Clinton. Rohrabacher told Mother Jones' David Corn that "there's not a person in this town who would not take a meeting to get material like that." A handful of Hollywood celebrities are getting ready to back Democratic candidates ahead of the midterms, The Hill's Judy Kurtz reports. Experts say that liberal celebs hoping to stymie Trump are likely to become more active over the next three months. GOP critics, however, were quick to point out what happened when celebrities went all in on Hillary Clinton's campaign. Forrmer President Obama on Wednesday also unveiled a list of 81 endorsements of Democratic candidates in races across the country. But Obama also kept his distance from some high-profile races. Notably not on the list were Alexandria Ocasio-Cortez and Rep. Beto O'Rourke (D-Texas), who is running for Senate. Race for the White House Sens. Bernie Sanders (I-Vt.) and Elizabeth Warren (D-Mass.) are both progressive icons and mulling whether to jump into the 2020 race. But as The Hill's Amie Parnes reports, many Democrats are worried that there might not be room for both of them in the Dem primary, which will feature a crowded but wide-open field. The two have worked together on some key issues, but there are growing tensions as 2020 nears. | 
