Washington (CNN) - It seems the passage of health care reforms into law has united the country in one way: It's sparked enthusiasm by both Democrats and Republicans to vote in this year's midterm elections, according to a new national poll.
But a CNN/Opinion Research Corporation survey also indicates that the passage of health care reform has not changed the political landscape in the battle for Congress. The poll's Tuesday release comes as President Obama signed into law a companion bill of "fixes" to the main health care legislation that he signed last week.
Fifty-five percent of Republicans questioned in the survey say they are now extremely or very enthusiastic about voting this November, up six points from January. Democrats are also up five points from January, with 36 percent of those questioned saying they are extremely or very enthusiastic about casting ballots in the midterms.
"The health care vote seems to have made some Democrats more eager to vote in November, but it has also activated more Republican voters, so the Democrats still face the same double-digit 'enthusiasm gap' they had before the vote," says CNN Polling Director Keating Holland.
But the survey also indicates that the passage into law of health care reform has not altered the battle for Congress.
According to the poll, the Republicans held a 48 percent to 45 percent advantage on the "generic ballot" question before the vote in the U.S. House on March 21 and they have virtually the same edge, 49 percent to 45 percent, a week later.
"Any gains that the Democrats may have made among women, white collar families or urban and suburban voters were essentially offset by losses among men, blue collar families and rural voters," says Holland.
Fifty-three percent of independent voters questioned say they would back the Republican candidate with 35 percent saying they would support the Democrat in the race.
But the poll also indicates that a sizable amount of respondents say their votes are not set in stone.
"Nearly 4 in ten registered voters said that they could change their minds, so handle these poll results with care - they are not, and cannot be, a prediction of what will happen in November," adds Holland.
The generic ballot question asks respondents if they would vote for a Democrat or Republican in their congressional district, without naming any specific candidates. The Democrats currently hold a 253-177 advantage in the House, with four seats that the Democrats once held vacant and one seat that the GOP held vacant. Republicans need to win 40 seats to take back control of the chamber.
Besides a surge in enthusiasm to vote in the midterm elections, the poll also indicates another change: The approval rating for the Democratic leaders in Congress has risen at a higher rate than the GOP's approval rating - restoring an advantage that the Democrats had through most of 2009. Forty-two percent now approve of how Democratic leaders in Congress are handling their jobs, up nine points from a week ago, with 36 percent saying they give Republican congressional leaders a thumbs up, a gain of four points over the past week.
"But both parties' approval ratings are still well below 50 percent, with little indication that a bump in approval ratings will translate into electoral strength in the fall," says Holland.
When it comes to the vicious political battle over health care, Republicans have been targeting House Speaker Nancy Pelosi. The poll suggests their strategy may be paying off. Fifty-four percent of those questioned disapprove of how she's handling her job, up six points from last May. Forty-three percent of those questioned approve of how she's handing her job.
The CNN/Opinion Research Corporation poll was conducted March 25-28, with 1,009 adult Americans questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.
–CNN Deputy Political Director Paul Steinhauser contributed to this report
Follow Paul Steinhauser on Twitter: @psteinhausercnn