This weekend’s polls confirmed again that the battle for the Senate may hinge largely on what happens in Iowa. Which means control of the Upper Chamber may turn to no small degree on this question: Can Joni Ernst run out the clock before her actual positions catch up with her, and eke out a victory through fundamentals, nostalgia-tinged appeals to conservative rural voters, and a deftly spun tale of clashing personalities that positions her as the true representative of “sturdy Iowa folk virtues“?

Democrats have long thought that once Ernst’s real views (the right-wing conspiracy-mongering about the United Nations; the opposition to the Department of Education and federal minimum wage; the outsized ideas about government dependency, etc.) were fully aired out, Democrat Bruce Braley would edge ahead. But Ernst maintains a small lead, calling into question that theory.

Now, in the final push, the Democratic Senatorial Campaign Committee is going up with a new ad that lacerates Ernst for signaling openness to privatizing Social Security, contrasting that with Democrat Bruce Braley’s flat-out opposition to privatization:

The ad, which is part of an ongoing multimillion-dollar buy, claims Ernst is “so extreme, she’d risk seniors’ retirement on the stock market, ending the guaranteed minimum benefit.” The ad offers no source for this claim, which looks like an extrapolation of the general risks involved with privatization. The spot does feature footage of Ernst saying: “Yes, I have talked about privatizing Social Security.” Ernst has subsequently confirmed she’s discussed privatization “as an option.” As PolitiFact notes, it’s going too far to say that Ernst would definitely do this, but it’s fair to say Ernst is open to doing it, and that embodies a real contrast between the two candidates.

A national Democratic strategist involved in the Iowa race tells me internal polling shows airing out Ernst’s true views on Personhood and Social Security is largely responsible for Braley bringing the race within two points.

The Ernst campaign’s own behavior suggests it is aware of the dangers of allowing for a full explication of her views and positions. Over the weekend, the Des Moines Register’s editorial board reported that it had invited her in for a discussion of its much-coveted endorsement, because it had not yet heard enough “specifics about her vision, priorities and positions.” Ernst skipped the meeting, and it seems fair to speculate that the Ernst camp worried that an extended discussion risked drawing her views into sharper relief.

When the Des Moines Register endorsed Braley the next day, it explicitly cited her openness to Social Security privatization as a key reason why. So expect Democrats to hammer away at this aggressively in the final stretch.

* GOP HOLDS EDGE IN BATTLE FOR SENATE: Over the weekend, NBC released a batch of polls showing Republicans leading in Colorado by one, in Arkansas by two, and Iowa by three. Greg Orman leads in Kansas by one and North Carolina is tied. All are within the margin of error.

Meanwhile, YouGov released a trove of data showing GOP leads in more than enough states to take the majority, but some are slim and Colorado and Iowa are tied. All this is consistent with the idea that the GOP is favored to take the Senate but that many of these races could still go either way.

* SENATE BATTLE REMAINS STABLE: Nate Silver analyzes the above data and concludes that not a lot has changed: Republicans hold a clear edge but not a decisive one, and a lot of uncertainty remains. Silver:

Part of the reason for the uncertainty is that many of the important races are associated with circumstances that produce larger polling errors. Louisiana will almost certainly have a runoff and Georgia is more likely than not to have one, which means there’s quite a lot of campaigning left in each state. The polling has been sparse in Arkansas and both sparse and inconsistent in Alaska. Kansas, and to a lesser extent Kentucky….Republicans have the edge, but they haven’t been able to put Democrats away.

Meanwhile, the FiveThirtyEight and HuffPollster models have the chances of a GOP takeover at around 63 percent — a clear advantage to Republicans but by no means a certainty.

 * SOME LARGER CONTEXT ON THE SENATE BATTLE: E.J. Dionne supplies it, noting that if anything, given the fundamentals, the battle for the Senate should not be as close as it is; Republicans should have dispatched more Dem incumbents by now; and they should have put more Dem seats in play. If Democrats must lose the Senate, limiting the GOP majority to 51 or 52 seats, which looks very plausible, is job number two.

* HOUSE GOP CONTEMPLATES GOVERNING: Politico has an interesting interview with number two House GOPer Kevin McCarthy, who explains that the GOP-controlled House must show the capacity to govern next year or lose in 2016. But:

Critics inside and outside the Republican establishment say the party’s revival is dependent on not only a functioning Congress, but passing policies like immigration reform — an uncertain prospect in a Republican-controlled Congress. McCarthy left open the possibility of passing an overhaul of immigration laws, but said if Obama “tried to do it by executive order, that’s the worst way,” and it would “stop everything.”

And so the groundwork is already being laid to blame Obama for the coming GOP failure on immigration, arguably the issue that poses the most pressing demographic challenge.

* QUESTION OF THE DAY: Washington Monthly asks a good one, and provides a possible answer: What ever happened to the House GOP lawsuit against the president?

* WHY WE’LL NEVER SPEND ON INFRASTRUCTURE: Paul Krugman makes it simple: Though America has long spent to upgrade its infrastructure and invest in the future, that isn’t going to happen now because one party opposes it.

Nowadays we simply won’t invest, even when the need is obvious and the timing couldn’t be better. And don’t tell me that the problem is “political dysfunction” or some other weasel phrase that diffuses the blame. Our inability to invest doesn’t reflect something wrong with “Washington”; it reflects the destructive ideology that has taken over the Republican Party….America has turned its back on its own history. We need public investment; at a time of very low interest rates, we could easily afford it. But build we won’t.

Your regular reminder: Republican lawmakers used to support infrastructure spending to create jobs, back before Obama was president.

* AND, YES, OBAMACARE IS WORKING: Don’t miss the New York Times’ terrific infographic detailing the real-world impact, by a number of metrics, of Obamacare a year after the website crashed. Overall conclusion:

After a year fully in place, the Affordable Care Act has largely succeeded in delivering on President Obama’s main promises, an analysis by a team of reporters and data researchers shows. But it has also fallen short in some ways and given rise to a powerful conservative backlash.

That the law has largely succeeded on core goals, but has given rise to a conservative backlash anyway, is why Republican Senate candidates are dissembling and evading endlessly on the true implications of their supposed support for repeal.