The United States midterm elections on Tuesday will likely to have a profound effect on its domestic policies, but will herald only a slight adjustment of attitude toward China on heated topics such as currency and trade issues, experts say. 

U.S. mid-term elections

With the election being the most expensive non-presidential vote ever in US history, a sluggish economy and high unemployment rates are the primary concerns for voters as they head to the polls to decide the future for Capitol Hill lawmakers.

As of press time, a Wall Street Journal/NBC News poll indicated the Republicans will gain votes needed to wrest control of the House, while making some gains in the Senate.

But the poll also showed the GOP (or Grand Old Party, as the Republicans are also known) is not likely to overtake the Democrats in the Senate.

US midterm elections are held two years after presidential elections that take place every four years. This year, all 435 seats at the US House of Representatives and 37 of the 100 seats in the Senate are being contested in the election.

The Democrats won overwhelmingly in the 2006 and 2008 elections, controlling both Congress and the White House.

The current landscape, however, has been overshadowed by widespread disillusionment with President Barack Obama for his perceived inability to jumpstart a foundering economy.

Consequently, the election results could well determine the effectiveness of the remainder of Obama's presidency.

The Republicans have repeatedly pledged to put "create jobs, cut taxes and shrink government" as their governing agenda. Should the Republicans take over the House, they are expected to roll back healthcare reforms, renew tax cuts for wealthy Americans, and reverse the Democrats' already stalled drive for comprehensive climate control legislation.

But any policy changes are not confined to strict, traditional bipartisan competition this year as the rise of the conservative Tea Party movement has added a new element to the election cycle.

The inexperienced Tea Party candidates, moreover, are likely to erode part of the Democrats' political power owing to overlapping opinions with the Republicans.

This year's pre-election campaign featured an unprecedented focus on China, when both the Democrats and the Republicans started war of words on yuan's appreciation and trade deficit to try to seek an edge over each other.