Much has been written of the damage Donald Trump has done to the Republican Party brand with his disruptive rhetoric and antics. But Hillary Clinton may also have put the Democratic Party brand in some peril with her secretive and evasive ways.
Ms. Clinton's unfavorable poll ratings may have a severely negative impact on the down-ballot fight for control of both the House and Senate this fall, as she strives to reclaim a working majority in a Congress for the Democrats. In GOP hands, Congress has plagued President Obama for six of his nearly eight years in the Oval Office.
If the strong Republican disfavor of Ms. Clinton bordering on hate generates a massive focus on maintaining party majorities in the Senate and especially in the House in November, as president she could face a continuation of the Republican legislative obstructionism that doomed much of the Obama agenda for so long.
Of the 34 seats up for election this year in the Senate, 24 are held by Republicans and 10 are to be defended by Democrats. With two independents already voting with the Democrats, Vermont's Bernie Sanders and Maine's Angus King, and Mr. Sanders finally identifying himself as a Democrat, Ms. Clinton's party only needs a pickup of four seats for the majority.
But the prospect of continued GOP obstruction in the House intensifies the likelihood of a battle royal this fall between House Speaker Paul Ryan, who aims to hold onto the wide GOP majority, and House Minority Leader Nancy Pelosi, an intense Clinton supporter who aims to restore her leadership.
At this stage in the presidential race, Mr. Trump seems much less likely to be interested than Ms. Clinton in focusing on the congressional races than on his own slipping presidential prospects.
Mr. Trump earlier showed such little concern about Republican control of Congress in the next administration that he lagged on endorsing either Mr. Ryan or Senate Majority Leader Mitch McConnell. Both finally endorsed him, but Mr. Trump didn't reciprocate until the news media hectored him about his failure.
Mr. Ryan has been rallying his House majority members to intensify their own fund-raising and re-election efforts in the wake of a Democratic National Committee push to capitalize on the down-ballot hemorrhaging it expects from Mr. Trump's increasingly polarizing candidacy.
The Republicans currently hold a big 59-seat bulge in the House, 247 to 188 Democrats, meaning they would need to pick up 30 to put Ms. Pelosi back as speaker. The intense dislike of Mr. Trump among most Democrats and many Republicans might fan Democratic hopes. But there appears to be an equally or perhaps greater Republican animosity toward Ms. Clinton, meaning the GOP faithful is likely to swell the party's down-ballot vote even as it walks away from Mr. Trump.
Ms. Clinton can expect a huge advantage from a solid turnout of women voters, spurred not only by the prospect of electing the first female American president but also by fury at Mr. Trump's fierce attack on a popular female Fox News telecaster, among other slurs toward women.
But in the end, Mr. Trump's sweetest revenge in the event of a humiliating landslide defeat might be diverting Republican energy and voting strength toward congressional races, in effect extending the Republican obstructionism of the last eight years through the next four years of a President Hillary Clinton.
Ms. Clinton is well aware that continued GOP control of one or both congressional houses could seriously jeopardize her own legislative agenda, already derided by the opposition as "third Obama term." But she will have two potent surrogates campaigning for her all fall -- the president himself and Vice President Joe Biden. They have already begun to weigh for Ms. Clinton in key battleground states like Pennsylvania, where Mr. Biden welcomed her to his native town of Scranton this week.
Mr. Trump will need all the help he can get from now on, including from all those Republican congressmen and senators seeking re-election against the tailwind of their foundering if still blusterous party standard-bearer.
Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is "The American Vice Presidency: From Irrelevance to Power" (Smithsonian Books). His email is juleswitcover@comcast.net.