For a party that is presumed to be heading for disaster in the midterms this November, the G.O.P. had a pretty good week. Its leadership in Congress, which is looking to head off a “blue wave,” received encouraging news on three different fronts: primary results, opinion polls, and fund-raising. On Friday, Charlie Cook, the editor and publisher of the Cook Political Report, which is widely read in Washington, posted an analysis under the headline “Glimmers of Hope for the GOP.”

Before examining some of these glimmers, it is important to note that the basic equation hasn’t changed. Several factors that always play key roles in midterm elections—the President’s unpopularity, grassroots mobilization, and the historical tendency for ruling parties to suffer losses—still favor the Democratic Party, particularly in the House, where twenty-three Republicans are defending seats in districts that Hillary Clinton won. To gain control, the Democrats need to flip twenty-four seats.

But there is no room for complacency among Trump’s foes, particularly regarding the prospects in the Senate, where the electoral map strongly favors the G.O.P. Ten Democrats are facing reëlection races in states that Trump carried. The Democrats’ chances of picking up Republican seats are probably limited to four states: Arizona, Nevada, Tennessee, and Texas.

In last year’s special election for one of Alabama’s Senate seats, the Republicans self-destructed by nominating an accused child molester, Roy Moore. In West Virginia on Tuesday, four out of five voters in the Republican Senate primary voted against Don Blankenship, the former mining C.E.O., who was sentenced to a year in jail after twenty-nine coal miners were killed at one of his mines. The winner was the state’s attorney general, Patrick Morrisey, who will face the incumbent, Joe Manchin, a Democrat. In Indiana and Ohio, where there were two more important Senate primaries, candidates acceptable to the national Republican leadership also prevailed.

On the polling front, a new survey from CNN indicated that the Democrats’ lead in the generic congressional vote is now just three percentage points. A second survey, from Reuters/Ipsos, put the Democrats’ lead at just one point.

To be sure, these findings should be interpreted skeptically. A third survey, from The Economist/YouGov, put the Democrats’ lead at nine points, which represented an increase of six points compared to the previous survey from that pollster. Poll averages, which aggregate the results from all the recent polls, are generally more reliable. The Real Clear Politics poll average puts the Democratic lead at 6.1 percentage points; 538’s version puts it at 6.2 percentage points. Still, these figures represent a significant change from the start of the year, when the Republicans were trailing by double digits in many polls.

Trump’s poll numbers have also moved up a bit during the past few months. With the economy strong and encouraging signs emerging from Korea, this trend appears to be gaining momentum. Gallup’s latest weekly update put Trump’s approval rating at forty-two per cent, the highest level since May of last year. Other polls are showing a similar pattern. Cook rightly pointed out that Trump’s rating is still very low by historical standards, and that the only modern President to have such a low approval rating at this point in his Presidency was Jimmy Carter. But Cook also noted, “For all of Trump’s ill-advised statements and actions, the wheels have not completely come off of the bus.”

Further Reading New Yorker writers on the 2018 midterm elections.

Then there is the question of fund-raising, which unfortunately can never be ignored. So far during this electoral cycle, Democrats have outraised Republicans in many districts, creating a good deal of concern in G.O.P. circles. But this week it was confirmed that Sheldon Adelson, the ultra-conservative billionaire casino mogul, has agreed to donate thirty million dollars to the the Congressional Leadership Fund, a Republican super PAC. The donation is three times as large as the one Adelson made in 2016. According to Politico, it came after the Speaker of the House, Paul Ryan (who announced last month that he would not seek reëlection) and other senior Republicans flew to Las Vegas and “laid out a case to Adelson about how crucial it is to protect the House.”

Facing the possibility of being impeached if the Republicans lose control of Congress, Trump surely doesn’t need any persuading about the importance of the coming elections. On Thursday night, he revved up a large crowd in Indiana, where the Democratic senator Joe Donnelly is facing a tough reëlection battle. The event provided a preview of how the Republicans will use Trump to target states and districts that he carried in 2016. In a speech that the Washington Post described as “remarkably on message—for him,” the President warned the crowd that, if Donnelly won, he and the Democrats would “raise your taxes,” “destroy your jobs,” and “knock the hell out of your border.”

As the election approaches, Trump will do a lot more of these rallies. To the extent they remind voters of his existence, it will be bad news for many G.O.P. candidates. Particularly in suburban Republican districts in states such as California, New York, New Jersey, and Pennsylvania, Trump still represents electoral poison for Republicans. That’s why so many G.O.P. incumbents have announced their retirement from politics. And it’s why a Democratic takeover of the House remains the most likely outcome in November.

But the message of this week is that the G.O.P. intends to put up a fight. For the blue wave to materialize, particularly in the Senate, the anti-Trump mobilization will need to be sustained and well-directed at all levels of the Party. Members of the Resistance, take note.