Republicans were declared winners in some key Senate races early on Tuesday evening and were projected to win control of the US House of Representatives, pointing to a shift in power that was likely to cripple President Barack Obama's policy agenda.
Here is some reaction from analysts to the midterm elections and their policy implications once the votes are counted:
* Jim Kessler, vice president for Policy at Third Way, a moderate progressive think tank
After the election, Obama will need to reorient his party. "He needs to lead the Democratic Party in a new and modern direction. The party needs to transform from one that is focused principally on economic security to one obsessed with economic growth ... The 80-year quest to construct a sound safety net is now over."
If Republicans capture not only the House of Representatives, but the Senate as well, "it would be a punch in the stomach" for Obama.
He could govern with Republicans in control of both chambers of Congress, as President Bill Clinton did.
"However, I wouldn't expect much in terms of agreement in the first year ... the best a Republican Senate could do is thwart a future Obama agenda. With Obama holding the veto pen, the GOP could only do so much."
* David Min, associate director, Center for American Progress, a moderate think tank
"Legislative gridlock would encourage Tea Party activists, but it would restrict Washington's ability to respond to potential further economic distress and to give the economy another shot in the arm. "Clearly it's not going to be from fiscal stimulus at this time."
"We could see some reckless activity in the cessation of spending ... Worse than gridlock, we could see a shutdown of normal government activity. That would have a significant effect on economic growth, an anti-stimulus if you will."
* Ethan siegal, analyst, The Washington Exchange, public policy advisory firm
"The newly elected crop of House and Senate Republicans will see their mission as not to compromise and cut deals with President Obama, but rather to destroy his remaining agenda and undo healthcare and financial services reform ..." "This will be a positive sentiment election for investors -- they will get the peace of mind they want, at least for a day or two, until the Bush tax cuts issue resurfaces."
* Robbert Van Batenburg, head of equity research, Louis capital markets
"It looks to be a good start for Republicans who gained comfortably a Senate seat in Indiana, and where the iconoclastic tea party favorite Rand Paul won in the Kentucky midterm elections."