​2016 by the numbers: A close general election?

Donald Trump and Bernie Sanders both picked up victories on Tuesday night, but the results didn't change much in terms of the overall state of the primaries. For Trump, that's good news; for Sanders, not so much.

Sanders won West Virginia handily, beating Clinton 51 to 36 percent and picking up 18 delegates in the process. Clinton only picked up 11. His victory, though, barely chipped into Clinton's delegate lead, meaning she remains the overwhelming favorite to win the nomination.

Hillary Clinton takes aim at Donald Trump

CBS News now estimates that Clinton has 2,239 total delegates, including superdelegates, who are not bound by the results of their state's primary. That's 94 percent of the 2,383 delegates she'd need to win the nomination. She needs only 144 more delegates to put her over the top - about 13 percent of the remaining delegates on the table. At her current pace, she'll clear that threshold and claim victory in early June.

Sanders, by contrast, cannot win 2,383 delegates by relying on the remaining pledged delegates exclusively. He'd need to win 87 percent of the pledged delegates left on the table, plus he'd need to win the support of the remaining uncommitted superdelegates and persuade some Clinton-aligned superdelegates to change their minds.

The Vermont senator has said he hopes to be able to persuade more superdelegates to support him after winning a majority of pledged delegates. But even this more modest goal seems almost impossible for him to reach. She's currently ahead of him by almost 300 pledged delegates. To surpass her, he would need 68 percent of the remaining pledged delegates available -- a much greater share than the 45 percent he's won so far.

On the Republican side, the results were even less consequential, as Donald Trump has already assumed the mantle of presumptive nominee. He won all of Nebraska's 36 delegates and at least 30 of West Virginia's 34 delegates, bringing his total to 1,131. At this point, he needs only 106 more delegates to obtain the 1,237 necessary to win the nomination on the first ballot. He's on pace to do that by early June.

A close race in November?

The conventional wisdom seems to be that Clinton holds an advantage over Trump at this early stage in the general election. That's not entirely without merit -- national polls consistently show Clinton beating Trump, some of them by double-digit margins -- but some new polls out of swing states this week show a much closer race in some key battleground states than analysts might expect. And that's a big deal because, as we know, the presidency won't be decided by a national vote, but by the Electoral College on a state-by-state basis.

Hillary Clinton woos anti-Trump Republicans

In a Quinnipiac survey released Tuesday, Clinton barely led Trump, 43 to 42 percent, in Pennsylvania. In Florida, she was also ahead by one point, 43 to 42. But in Ohio, perhaps the paragon of a swing state, Trump was ahead, 43 to 39 percent.

In New Hampshire, the race is also close -- according to a Darthmouth University poll released Monday, Clinton is guarding a small lead over Trump, 34 to 29 percent.

These results may be jolting some Democrats out of their sense of complacency. For all the Democratic optimism about Clinton's chances in November (and there's still quite a bit of optimism), the 2016 election is likely to be a hard-fought contest in the same battleground states that have decided the past few presidential elections - places like Ohio, Florida, and Pennsylvania, along with Virginia, Colorado, New Hampshire, Iowa, North Carolina, New Mexico, and Nevada.

After Trump emerged as the presumptive GOP nominee, there was talk in some Democratic quarters that Clinton could expand the map by playing in red states (like Utah, for example) that rejected Trump in the GOP primary. But if the polls of traditional battleground states continue to show as close a race as this latest Quinnipiac survey, though, you can expect Democrats to rein in those ambitions, and quickly.

CBS News' Jennifer De Pinto contributed to this report.