Democrats have their best chance for a decade to win control of the Senate this November. With Republicans defending 24 seats to Democrats’ 10 and the presumed turnout advantage in presidential elections, getting the necessary five net pick-ups looked almost like a foregone conclusion. Instead, as CNN notes, Democrats are beginning to worry that it’s turning out more like a missed opportunity — and they’re looking at the fumbling Hillary Clinton campaign as the culprit:

Less than two months until Election Day, Democratic confidence has been shaken, as Hillary Clinton suddenly finds herself trailing Donald Trump in some swing states and a fresh batch of polls show GOP incumbents in the lead. …

In Ohio and Florida, GOP incumbents now have double-digit leads, according to a new CNN-ORC poll released Wednesday, undercutting Democratic efforts to pick up seats once viewed as prime opportunities. In New Hampshire, two polls show Republican Sen. Kelly Ayotte now in the lead after falling behind Gov. Maggie Hassan last month. And in Nevada, Rep. Joe Heck holds a slight edge over his Democratic challenger Catherine Cortez Masto, buoyed in part by Trump’s sudden resurgence in their state.

This comes as other seats that once appeared within reach, like John McCain’s in Arizona, seem to be a steeper climb. And a prized Democratic recruit in Indiana, former Sen. Evan Bayh, has stumbled on the campaign trail, seeing his once commanding lead now shrinking to single digits.

One thing in common: Trump has all-but-erased Clinton’s lead in some of the key battleground states with major Senate races, according to a batch of new public opinion polls. He’s up by 5 points in Ohio and 3 in Florida, according to the CNN-ORC poll.

Relying on Hillary Clinton may have been their first mistake. She is a terrible candidate, one who nearly lost the nomination to a socialist Senate backbencher that didn’t identify as a Democrat until running for the presidency. In every election cycle since 1992 except one (2006), Hillary’s favorables have gone underwater — and stay there until after it’s over. That, plus all of the baggage of Clinton scandals that now include the Clinton Foundation and her e-mail server and all of the lies she’s told about both, have become a millstone around the neck of Democrats.

Democrats have more than one millstone, however. In my column for The Fiscal Times, I draw lines between Democrats’ Senate woes and the millstone of their own making — ObamaCare. The disaster that has been coming for more than six years will explode one week before the election, but it’s already taking its toll now:

Democrats promised that government control over this marketplace would “bend the cost curve downward” and result in an average reduction of $2500 in annual premiums for a family of four; instead, more of their disposable income and savings have gone to health insurance and out-of-pocket expenses.

The dislocation of Obamacare consumers in many more states may have an even worse impact on Democrats. Voters in almost all key battleground states have at least one insurer pulling out of the exchanges, and in some cases more. Ohio will lose two insurers in every county, which will force consumers to find new policies at ever-higher prices.

Arizona, where John McCain looked vulnerable, will lose one insurer in every county, and one county won’t have any options in the Obamacare exchange. In four other key states for Senate control, according to the Kaiser Family Foundation, more than half of all counties will lose at least one insurer: Florida, North Carolina, Colorado, and Wisconsin.

Don’t think these failings have escaped voters’ attention, either. A Morning Consult poll released this week shows far more people have experienced cost increases in every phase of health care than have seen reductions over the past year. Forty-three percent have had increases in premiums, while only 8 percent have saved money.

Voters have already had ample access to reporting on these issues, but perhaps have not paid much attention to them. In October, though, ObamaCare exchange consumers will start getting notices from their current insurers about the cancellation of their plans in the open enrollment that will start on November 1. They will have to find new insurance and will discover the massive increases in premiums and deductibles that all but assure them of having less disposable income in 2017. Even those who get their insurance through their employers will have to face the higher deductibles and premiums that ObamaCare failed to prevent, starting in October as well.

If Democrats think their Senate chances look bad now, just wait for the next few weeks. Team Trump and GOP candidates for the Senate and House should focus on the hardship and failure of Democrats’ arrogance — and show voters how to make them pay for it.

Update: “In a decade” should be “for a decade” in the opening sentence; fixed it, and thanks to James Taranto for pointing it out.