Demonstrators march against amnesty for immigrants in the U.S. illegally during a July 15 rally against the immigration reform bill in Washington. (Jose Luis Magana/Reuters)

Majorities of Americans support the two main pillars of immigration reform — increasing border security and a path to citizenship for undocumented immigrants. But partisan, racial and ethnic divisions damp overall public support for a comprehensive reform package, according to a new Washington Post-ABC News poll.

The survey highlights the complexity of public attitudes on an issue that is at the center of President Obama’s second term agenda. The findings also underscore how the legislative battle ahead presents House Republicans with the prospect of satisfying the party’s base at a cost of diminishing the party’s prospects of winning future national elections.

Half of all Americans — and 83 percent of Hispanics — say they would be disappointed if the House does not pass legislation instituting a path to citizenship. But Republican rank-and-file oppose such a provision, making it a central sticking point in GOP deliberations over the legislation.

Republican leaders have highlighted Hispanic outreach as a major part of their strategy to win the White House in 2016. But the poll shows that Republicans would bear the brunt of responsibility should a path to citizenship not be included in the final bill.

Tension over immigration is not the only challenge facing Republicans, according to the poll. For the first time in Post surveys, a slim majority of rank-and-file Republicans disapprove of the direction that the party’s leadership is taking the GOP.

Political head winds: Immigration proves a bind for GOP

The poll also reminds Democrats of the head winds they may face in the 2014 midterm elections as they fight to hold their majority in the Senate and make inroads in the GOP-controlled House. Public impressions of the president’s signature health-reform law are still more negative than positive, and the detractors are more passionate about their views than advocates.

In addition, Obama’s approval rating stands at 49 percent, dipping under 50 percent for the first time in nearly a year. And on the eve of a new round of speeches by Obama highlighting his economic agenda, assessments of his handling of the economy remain slightly negative and show no sign of improving.

On immigration, the focus is now on the House, where GOP leaders face a series of difficult policy and political choices.

The Senate recently approved a comprehensive bill that includes a path to citizenship and about $46 billion in new spending on border security. Overall, Americans divide evenly on the bill, with 46 percent supporting the package and 44 percent opposing. Among Hispanics, 66 percent back the Senate bill, as do 50 percent of independents (with 40 percent against).

Among Republicans, however, 62 percent oppose the Senate package, most saying they strongly oppose it. An identical 62 percent of Republicans say they would be relieved if the House opted against a path to citizenship in any form.

Last week, a Washington Post-ABC News poll found clear majority support for both the pathway to legal status and tighter border controls, even with its multibillion-dollar price tag. Still, relatively few in that poll — particularly among Republicans — supported both major components, an indication of the challenges ahead for those seeking to build a majority coalition for comprehensive legislation.

Given the higher support for the individual pieces of the bill, it is not surprising that most Americans, 53 percent, say they want the Senate bill broken into individual pieces and considered separately. Support for breaking up the components peaks at 66 percent among conservative Republicans; it is lowest among Hispanics at 43 percent. Half of all Democrats also say it should be broken into pieces.

The lack of support for the direction charted by GOP leaders generally only adds to the party’s problems. The 52 percent who say they believe the leaders are taking the party in the wrong direction is nearly double the percentage who said so just before the Republican National Convention in Tampa this past August.

Nor does there seem to be a consensus on what direction the party ought to take. About six in 10 moderate Republicans and GOP-leaning independents say their leadership is moving the party in the wrong direction. But so do 53 percent of those who self-identify as “very conservative.”

In all, 62 percent of Republicans say they prefer that political leaders cooperate with Democrats, while 32 percent say they should hold firm to their positions and principles. But dissatisfaction with the direction charted by GOP leaders is about equal in both groups.

Democrats are far more united behind their leaders. Fully 72 percent of Democrats and Democratic-leaning independents say their leadership is taking the party in the right direction, a six-point increase from last year. Eighty percent of Democrats say they approve of the way Obama is handling his job as president.

Still, the president’s strong support among Democrats is as low as it has been in nearly a year, at just 47 percent. At 40 percent, the number of moderate and conservative Democrats who strongly approve of his job performance is at a nearly two-year low and is 20 points below where he was among the group after winning reelection.

Moderate and conservative Democrats are evenly divided on the Affordable Care Act — 46 percent support and 47 percent oppose, and half say they approve of the recently announced one-year delay for the employer mandate. These numbers are in stark contrast to liberal Democrats: 78 percent are supportive of the overall reform law and 59 percent disapproved of the delay.

The poll was conducted July 18 to 21 among a random national sample of 1,002 adults. Results from the full poll have an error margin of 3.5 percentage points.

Cohen is polling director at Capital Insight, the independent polling group of Washington Post Media. Capital Insight pollsters Scott Clement and Kimberly N. Hines contributed to this report.