President Barack Obama has little to show so far for a second term stifled by political inertia at home and foreign crises that have defied American might and influence.

Nearly six months after delivering an inaugural address brimming with liberal intent, Obama is in a familiar spot: banging his head against a brick wall of Republican opposition.

Big hopes of action on immigration, the economy and taxation are fading, meaning Obama's second term may be more about cementing gains of his first four years than adding to his legacy.

With the Middle East aflame, allies angered by US spy snooping and amid challenges from North Korea and Iran, Obama may also look in vain for wins abroad that second term presidents crave.

Vindicated by voters, Obama returned to the White House with vigor in November. But there has been little to cheer since.

He did secure victory over Republicans in a row over raising tax rates on the rich at the turn of the year.

But since, he has seen a gun control drive crumble and had to delay implementation of part of his top achievement, the ObamaCare health overhaul.

Rows over National Security Agency (NSA) eavesdropping programs exposed by fugitive leaker Edward Snowden have meanwhile consumed presidential energy.

And Obama is known to be frustrated that a clutch of political scandals -- which he sees as frivolous -- have whipped up media outrage and forged an opening for Republicans.

He is said to chafe at critiques of his incapacity to bend Congress to his will, and out-of-context comparisons to legislative alchemists such as ex-president Lyndon Johnson.

"Barack Obama is in a slump," said Peter Brown, director of the Quinnipiac University Polling Institute, unveiling data showing the president's approval rating had dipped to 44 percent.

Obama's rating on foreign policy -- a strength during last year's election -- hit a worst-ever 40 percent, as he struggled to keep pace with carnage in Syria and a coup in Egypt.

Obama had hoped that a thumping election victory would break the "fever" he diagnosed in a Republican Party dedicated to thwarting his presidency.

Some hope.

"Sadly, all too often, we're not getting much cooperation from the other side," Obama complained at a Democratic Party event in Miami in June.

"They seem more interested in winning the next election than helping the next generation."

Bruce Buchanan, a specialist on the presidency at the University of Texas, says Obama's struggle with his foes is unique in modern times.

"I don't think any other president has had quite this difficult situation in terms of the other party's visceral hatred of him," he said.

The struggle is rooted in a sincerely felt ideological clash between conservatives who view government as the problem and Obama's reflex to wield state power to meet his era's challenges.

Currently, the Republican-led House of Representatives is holding hostage Obama's best bet for a significant second-term domestic achievement -- immigration reform.

Many House Republicans fear challenges from their right in 2014 primary contests if they pass a bill to give 11 million illegal immigrants a path to citizenship.

But hopes the logjam may break are validated by fears of national Republican leaders that continuing to infuriate Hispanic voters -- for whom immigration reform is a key issue -- could lead to years in the political wilderness.

The immigration debate encapsulates Obama's paradoxical political plight: so toxic is his image among Republicans that his best chance of getting something done is stay on the sidelines.

Congressional opposition also shapes Obama's strategy on tackling global warming, which he hopes to make a centerpiece of his second term.

Knowing climate change bills are dead on arrival in Congress, he ordered officials to write strict new rules to curb emissions at power plants.

He may also need to use executive power to bypass Congress to fulfill another promise renewed in his second term, closing the war on terror jail at Guantanamo Bay.

With big wins elusive, Obama may use his second term to secure earlier achievements for posterity, a common pursuit of two-term presidents.

This will require smooth implementation of ObamaCare, and a continued slow mending of the US economy.

Obama got little kudos for containing economic meltdown when he took office in 2009, but his role, including saving the US auto industry, may draw more praise over time.

"I don't know that he gets a lot of short term credit for that," said University of New Hampshire political scientist Dante Scala.

"Maybe, he gets long-term historical credit down the road."

Abroad, cementing his legacy means Obama must wind down NATO combat in Afghanistan without leaving chaos behind.

And he must also navigate the Iranian nuclear showdown and the war in Syria without again embroiling US forces in the Middle East.