The American political landscape is likely to be redrawn as the Republicans anticipate big gains in the U.S. mid-term elections

In the run-up to election day, Obama has been spending several days each week away from the White House, campaigning around the country for vulnerable Democratic candidates facing close races against their Republican opponents.At a recent election rally in Madison, Wisconsin, Obama reminded supporters what the Democrats risk losing if they fail to hold off the Republicans.

"Make no mistake, if the other side does win, they will spend the next two years fighting for the very same policies that led to this recession in the first place. The same policies that left the middle class behind for more than a decade. The same policies that we fought so hard for to change in 2008," Obama said.

Democrats presently control the House of Representatives by a margin of 255 seats to 178 seats for the Republicans. Two seats are vacant. In the Senate, the Democrats have a margin of 59 to 41 cover the Republicans. All 435 seats in the House and 37 seats in the Senate are decided on election day.

While a favorite armchair game in Washington has long been the prediction of voter sentiment on election day, only a fool would bet an electoral outcome with certainty. Voters in U.S. congressional elections can be finnicky and notoriously unpredictable. That said, for many analysts the November vote is regarded as a referendum on the two-year long presidency of Barack Obama.

The stakes are huge. This will be a referendum on one party rule, both in the House and the Senate and most importantly, the President. The President said a year ago that if the American people don't like my policies, then they can speak, and they will speak at the ballot box, and he is prepared to take his medicine, and I believe he is going to get a heavy dose," said Bradley Blakeman, a former top White House adviser to President George W. Bush.

Perhaps the most probable outcome is a divided Congress -- with Republicans assuming control of the House with a majority of 218 or more seats, and the Democrats retaining control of the Senate, although with a reduced majority.

If the Democrats lose the House, Obama will soon feel the brush of an unusually rude awakening. The forecast Republican majority will be studded with a number of newly elected members of Congress from the so-called Tea Party movement, the loosely affiliated group of conservatives who embrace opposition to Obama's policies with nearly religious zeal.

"Suddenly the House will go from being the most progressive chamber to being the one that represents the most right wing sectors of the Republican party," said Jennifer Palmieri of the Center for American Progress, a Democratic think tank.

The steeper challenge for the Republicans will be in the U.S. Senate, where 10 new seats will be needed to assume control. It is not impossible, but for the Republicans to win the Senate, all the stars in the U.S. political cosmos must align.

In the midterm election of 1994, with Bill Clinton in office for two years, the Republicans swept out the Democrats from control of both the House and Senate. The new balance of power required Clinton to govern with a more bipartisan hand. Even with only one chamber of the U.S. Congress lost to the Republicans, Obama may find that he must do the same.

"And if he were smart, he would start reading up on what Clinton did after 1994. Clinton realized that in order to provide the kind of accomplishment he needed to get re-elected, he had to work across the aisle," Blakeman said.