Midterm elections have always been a headache for the White House incumbent, and the upcoming one may be even more troublesome for the Democrats, with Barack President Obama practically unwelcomed by so many candidates.

Even so, the president is undaunted and is making appearances in places where he has been successful in the past and where the Democrats are in a tight race, whether for Congress or the governor’s office.

Most important for the Democrats is holding on to the Senate. If the Republicans can muster six new seats, then they control Congress because the House appears to be theirs once again.

Obama’s current five-state tour includes a stop in Michigan Saturday, where his presence and influence are never in doubt, and the Democratic gubernatorial candidate, Mark Schauer, will need all the votes the president can deliver. Obama defeated Mitt Romney by 47 points here. His persuasion is also necessary for Gary Peters in his bid to be the new congressman. The latest polls show Peters with a double-digit lead over his opponent.

At the beginning of his campaign swing in Milwaukee, Obama spoke in a neighborhood where he won 99 percent of the vote in 2012. What clout he can deliver for Mary Burke, who is running against incumbent Republican Scott Walker for the Wisconsin governorship, will be critical because the two candidates are in a virtual dead heat. Maine’s gubernatorial race is also tight, and Obama hopes he can pump up things for Rep. Michael Michaud.

When Obama hits Philadelphia to boost the candidacy of Tom Wolf for governor of Pennsylvania, the situation is not as desperate, but in Connecticut, Gov. Dannel Malloy is facing a tough fight to retain his post.

While the gubernatorial races are important, of pressing concern for Democrats are the various Senate races around the nation, and the outcomes in Kansas, Iowa, North Carolina, Alaska and Kentucky may determine who controls the Senate. And it very well could bring a new minority or majority leader if the incumbent Mitch McConnell is bested by Alison Grimes.

Democrats appear to believe that Grimes has a good chance to overturn the longstanding senator, with Hillary Clinton making a second visit to the state this year, this time focusing on Lexington and the northern region of the state. A recent poll shows McConnell with nearly a 5 percent lead over Grimes, although she is hopeful that a batch of last-ditch ads will narrow that margin and turn the tide.

Yesterday, the Kansas City Royals evened the World Series, and in the state’s Senate race, which could be a game changer in Congress, the most recent poll shows Independent Greg Orman and the GOP’s Pat Roberts practically tied in the contest, although Orman may have a slight lead. A large number of voters are still undecided, and therein lies the rub or the outcome.

According to Nate Silver’s 538, which has an enviable record in predicting election results, the Republicans have a 62.3 percent chance of winning a majority of the Senate. Democrats have a 37.7 percent chance of keeping the majority. There is a 17.9 percent chance Republicans will control 52 seats and the Democrats will control 48 seats.

If this prediction holds true, then Obama will face an even tougher obstinacy from the GOP in his final two years as the nation’s leader, and getting certain appointments approved and bills passed, which have been almost impossible, will become all the more difficult and challenging.