Tougher limits on soot from smokestacks, diesel trucks and other sources were announced just over a month after the Nov. 6 election. These were foreseen: The administration had tried to stall until the campaign ended but released the proposed rules in June when a judge ordered more haste.

Regulations give teeth and specificity to laws are essential to their functioning even as they create bureaucratic bloat. Congress-skirting executive orders and similar presidential directives are less numerous and generally have less reach than laws. But every president uses them and often tests how far they can go, especially in times of war and other crises.

President Harry Truman signed an executive order in 1952 directing the Commerce Department to take over the steel industry to ensure U.S. troops fighting in Korea were kept supplied with weapons and ammunition. The Supreme Court struck it down.

Other significant actions have stood.

President Franklin D. Roosevelt issued an order in February 1942 to relocate more than 110,000 Japanese-Americans living on the West Coast to internment camps after Japan’s attack on the Pearl Harbor naval base. Decades later, Congress passed legislation apologizing and providing $20,000 to each person who was interned.

After the terrorist attacks of Sept. 11, 2001, President George W. Bush approved a series of executive orders that created an office of homeland security, froze the assets in U.S. banks linked to al-Qaida and other terrorist groups, and authorized the military services to call reserve forces to active duty for as long as two years.

Bush’s most contentious move came in the form of a military order approving the use of the military tribunals to put accused terrorists on trial faster and in greater secrecy than a regular criminal court.

Obama also has wielded considerable power in secret, upsetting the more liberal wing of his own party. He has carried forward Bush’s key anti-terrorism policies and expanded the use of unmanned drone strikes against terrorist targets in Pakistan and Yemen.

When a promised immigration overhaul failed in legislation, Obama went part way there simply by ordering that immigrants brought illegally to the United States as children be exempted from deportation and granted work permits if they apply. So, too, the ban on gays serving openly in the military was repealed before the election, followed now by the order lifting the ban on women serving in combat.

Those measures did not prove especially contentious. Indeed, the step on immigration is thought to have helped Obama in the election. It may be a different story as the administration moves more forcefully across a range of policy fronts that sat quiet in much of his first term.

William Howell, a political science professor at the University of Chicago and the author of “Power Without Persuasion: The Politics of Direct Presidential Action,” isn’t surprised to see commandments coming at a rapid clip.

“In an era of polarized parties and a fragmented Congress, the opportunities to legislate are few and far between,” Howell said. “So presidents have powerful incentive to go it alone. And they do.”

And the political opposition howls.

Sen. Marco Rubio, R-Fla., a possible contender for the Republican presidential nomination in 2016, said that on the gun-control front in particular, Obama is “abusing his power by imposing his policies via executive fiat instead of allowing them to be debated in Congress.”

The Republican reaction is to be expected, said John Woolley, co-director of the American Presidency Project at the University of California in Santa Barbara.

“For years there has been a growing concern about unchecked executive power,” Woolley said. “It tends to have a partisan content, with contemporary complaints coming from the incumbent president’s opponents.”

The power isn’t limitless, as was demonstrated when Obama issued one of his first executive orders, calling for closing the military prison at the Guantanamo Bay naval base in Cuba and trying suspected terrorists housed there in federal courts instead of by special military tribunals. Congress stepped in to prohibit moving any Guantanamo prisoners to the U.S., effectively blocking Obama’s plan to shutter the jail.

Among recent actions:

—Obama issued presidential memoranda on guns in tandem with his legislative effort to expand background checks and ban assault-type weapons and large capacity magazines. The steps include renewing federal gun research despite a law that has been interpreted as barring such research since 1996. Gun control was off the table in the campaign, as it had been for a decade, but the shooting at a Connecticut elementary school in December changed that overnight.

—The Labor Department approved new rules in January that could help save lives at dangerous mines with a pattern of safety violations. The rules were proposed shortly after an explosion killed 29 men at West Virginia’s Upper Big Branch mine in 2010, deadliest mining accident in 40 years. The rules had been in limbo ever since because of objections from mine operators.

—The government proposed fat, calorie, sugar and sodium limits in almost all food sold in schools, extending federal nutritional controls beyond subsidized lunches to include food sold in school vending machines and a la carte cafeteria lines. The new proposals flow from a 2010 law and are among several sidelined during the campaign.

The law provoked an outcry from conservatives who said the government was empowering itself to squash school bake sales and should not be telling kids what to eat. Updated regulations last year on subsidized school lunches produced a backlash, too, altogether making the government shy of further food regulation until the election passed. The new rules leave school fundraisers clear of federal regulation, alleviating fears of cupcake-crushing edicts at bake sales and the like.

—The Justice Department released an opinion that people with food allergies can be considered to have the rights of disabled people. The finding exposes schools, restaurants and other food-service places to more legal risk if they don’t accommodate patrons with food allergies.

—The White House said Obama intends to move forward on rules controlling carbon emissions from power plants as a central part of the effort to restrain climate change, which the president rarely talked about after global-warming legislation failed in his first term. With a major climate bill unlikely to get though a divided Congress, Obama is expected to rely on his executive authority to achieve whatever progress he makes on climate change.

The Environmental Protection Agency is expected to complete the first-ever limits on carbon pollution from new coal-fired power plants. The agency also probably will press ahead on rules for existing power plants, despite protests from industry and Republicans that such rules would raise electricity prices and kill off coal, the dominant U.S. energy source. Older coal-fired power plants have been shutting across the country because of low natural gas prices and weaker demand for electricity.

—In December, the government proposed long-delayed rules requiring automakers to install event data recorders, or “black boxes,” in all new cars and light trucks beginning Sept. 1, 2014. Most new cars are already getting them.

—The EPA proposed rules to update water quality guidelines for beaches and control runoff from logging roads.

As well, a new ozone rule probably will be completed this year, which would mean finally moving forward on a smog-control standard sidelined in 2011.

A regulation directing federal contractors to hire more disabled workers is somewhere in the offing at the Labor Department, as are ones to protect workers from lung-damaging silica and reduce the risk of deadly factory explosions from dust produced in the making of chemicals, plastics and metals.

Rules also are overdue on genetically modified salmon, catfish inspection, the definition of gluten-free in labeling and food import inspection. In one of the most closely watched cases, Obama could decide early this year whether to approve the Keystone XL oil pipeline from Canada to Texas.

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Associated Press writers Matthew Daly, Ricardo Alonso-Zaldivar, Mary Clare Jalonick and Sam Hananel contributed to this report.