DEVELOPMENTS

• President Barack Obama was back at the White House after making his final campaign appearances over the weekend. He raised tens of millions of dollars over two years for Democratic candidates, but in the races’ final days most members of his party opted not to appear in public with him because of his poor approval ratings.

• Early voting results do indicate that Democrats in some states, particularly in Iowa and North Carolina, were doing better than they had in 2010. But such efforts usually matter only when results are extremely close.

• Presidential hopefuls were wrapping up their surrogate campaign duties. Sen. Rand Paul of Kentucky was with McConnell. Former Republican Sen. Rick Santorum of Pennsylvania lent his tea party appeal to conservative House members Patrick McHenry and Mark Meadow, both seeking re-election in North Carolina.

— From news services

WHAT TO WATCH FOR

EARLY STATES

Is there a Republican wave starting? Watch New Hampshire, North Carolina and Georgia, three of the earliest poll closings, where Senate races are close. Also check Maryland and Connecticut, two reliably Democratic states. If the party's gubernatorial candidates face trouble, that's a strong clue Republicans are in for a huge night. And keep an eye on black voter turnout in the South and Hispanic turnout in the Northeast and Colorado. If it's way down from 2012 levels, Democrats are in trouble.

THE MIDDLE

Five states — Kansas, Colorado, Iowa, Arkansas and Louisiana — could determine Senate control. All five races could be tight, with results not clear Tuesday night.

LATE STATES

Senate control could come down to Alaska, a state notoriously hard to forecast thanks to its independent and largely rural nature. Because many cities are so remote, it’s even hard to predict when the count in the battle between Sen. Mark Begich, a Democrat, and Republican Dan Sullivan will be final. Also be alert for middle-of-the-night stunners?, such as an upset in Senate races in Oregon and Minnestoa.

— McClatchy Newspapers

“The spending, the borrowing, the taxing, the overregulation, the slow growth. … These people need to be stopped,” Sen. Mitch McConnell of Kentucky said of the Democrats on Monday, urging voters to support him and GOP candidates everywhere

McConnell would be in line to control the Senate’s agenda as majority leader if Republicans win today.

Democrats weighed down by Obama’s sagging approval rating kept their distance from him and looked to a costly turn-out-the-vote operation to save their seats and their majority.

“There are two people on the ballot tomorrow: me and Scott Brown,” said Sen. Jeanne Shaheen of New Hampshire, who faces a strong challenge from GOP nominee Scott Brown, pushing back against the Republican effort to turn the vote into a referendum on Obama’s policies.

The cost of the campaign climbed toward $4 billion, and there seemed to be no end to the attack ads on television.

All 435 House seats are on Tuesday’s ballot, and not even Democrats predicted they would be able to take control away from the Republicans. Instead, they concentrated on protecting their incumbents, a strategy that meant tacitly conceding races in Utah, New York and North Carolina where retirements created opportunities for Republicans to pad their majority.

The lack of suspense about the House made control of the Senate the election’s main prize.

Republicans need a gain of six seats to capture the majority. They were all but assured of winning Democratic-held seats in West Virginia, Montana and South Dakota, and Democrats held out little hope that Sen. Mark Pryor of Arkansas could win re-election.

Polls suggested that races in Iowa, Colorado and Alaska were tilting the Republicans’ way, too — although Democrats said their get-out-the-vote operation made any predictions unreliable.

There were also competitive races in Shaheen’s New Hampshire and in North Carolina.

Strategists in both parties said Louisiana and Georgia were both likely headed for runoffs, the first in December and the second in January, which could delay the final verdict on Senate control.

The wildest wild card of all was in Kansas, where polls said 78-year-old Republican Sen. Pat Roberts was in a close race with independent Greg Orman.

Early voting topped 18 million ballots in 32 states, and both parties seized on the number as evidence of their own strength.

Pre-Election Day ballots in Wisconsin were more than double those for the 2010 midterms, evidence of high voter interest in the race between Republican Gov. Scott Walker and Democratic challenger Mary Burke.

Wisconsin was one of 36 states with gubernatorial elections on the ballot.

Money flowed into states with competitive races, with the North Carolina race between Democratic Sen. Kay Hagan and Republican challenger Thom Tillis topping $108 million. Of that total, $76 million was spent by outside groups trying to influence the outcome.

Not surprisingly, there was controversy to the end in a campaign filled with it.

In Iowa, retiring Democratic Sen. Tom Harkin drew attention for his weekend remark that Republican Joni Ernst was wrong for Iowa even if she was “as good looking as Taylor Swift.”

Ernst said she was offended by the comments and added that if she were a man, “Harkin wouldn’t have made” them.

Harkin issued a statement saying he knew he shouldn’t have, “but I am only human and I can make mistakes sometimes in how I say something.”

A new poll conducted by NBC News and The Wall Street Journal on Monday found that likely voters favor Republican control of Congress by a single percentage point, 46 percent to 45 percent. The same poll showed voters favoring Republicans 49 percent to 43 percent in 2010 just before Republicans seized control of the House and made large gains in the Senate.