Whichever party wins the American presidency in November, Republicans are likely to remain in the majority in the House of Representatives while the Democrats could well retain their control of the Senate.

After the spectacular success of the Republican Party in the 2010 congressional elections, when it won 63 House and six Senate seats, the 2012 election seemed a golden opportunity to reclaim control of both chambers of Congress. Republicans are defending only ten Senate seats next month compared to 23 on the Democratic side, several of them in conservative states such as Missouri, Montana, North Dakota and Virginia.

Preelection polls suggest that a Republican sweep is anything but likely, however. Even in Arizona and Indiana, deep red states, the race is far too close for Republicans’ comfort.

The possibility of the Democrats retaining their majority in the upper chamber stems at least in part from the same mistake that the Republicans made in 2010 — nominating candidates that are too far out of the mainstream to appeal to centrist voters. The nomination of outspoken Tea Party candidates in Delaware, Colorado and Nevada two years ago denied the Republicans three Senate victories that could have been achieved if moderate conservatives, such as Scott Brown in Massachusetts, had been on the ballot.

Brown may yet lose this year’s election to Democrat Elizabeth Warren but the fact that he won a seat that had been occupied by a Democrat since 1972 in one of the most left-wing states in the country was remarkable. By contrast, Harry Reid decisively defeated Tea Party candidate Sharron Angle in Nevada in 2010 even if his approval rating had been under 40 percent during the summer.

This year, Republican primary voters have nominated a professional wrestling magnate in Connecticut, a congressman who believes that there is a distinction between “legitimate” and illegitimate rape in Missouri and voted out one of the most conservative members of the Senate, Richard Lugar, in Indiana in favor of a more right-wing candidate who is struggling to protect a seat that has been in Republican hands since 1977.

Republicans are also almost certain to lose the Maine Senate seat that opened up due to Olympia Snowe’s retirement. She was considered one of the most centrist Republican legislators and cited Washington’s “hyperpartisan” environment as reason to quit.

If the United States continue to have divided government post November, partisanship will have to be reined in, however — and quick because the “fiscal cliff” looms. Unless Congress acts, $100 billion in spending cuts and $440 billion in tax increases will be automatically enacted in January of next year. Economists predict that half a trillion in sudden deficit reduction will plunge the country back into recession, even if it won’t actually balance the budget.

To balance spending in the long term, comprehensive entitlement and tax reform is needed. For the last two years, the two parties haven’t been able to compromise. Democrats refuse to reform entitlements; Republicans won’t raise taxes. Neither party has yet given any indication that is willing to meet the other halfway on these issues.

For Republican lawmakers in particular, to compromise could be dangerous. If they vote to raise taxes, they may well face a primary challenge from the right in two years’ time.