30 July 2014 Last updated at 19:29

What are presidential executive orders?

Republicans in the House of Representatives have begun the process of suing President Barack Obama, accusing him of exceeding his constitutional authority when he unilaterally delayed an insurance coverage deadline written into his 2010 healthcare overhaul.

White House officials dismiss the lawsuit as a political stunt - and say the president has constitutional authority to change the deadline.

Mr Obama's critics say he has overreached in his authority. They claim he has gone too far with this and other executive actions on healthcare and politically contentious issues, from immigration and gay rights to the environment and a prisoner exchange with the Taliban.

Like US presidents before him, Mr Obama has issued dozens of executive orders, according to researchers at the University of California-Santa Barbara's American Presidency Project, and many, many more memoranda and proclamations.

What is an executive order?

The president regularly issues orders to manage the executive branch of the federal government, weighing in on everything from White House office decorations to foreign policy. Sometimes "the president decides to put those directions on paper, and that becomes an official document," explains Ilya Shapiro, a senior fellow at the libertarian think-tank Cato Institute.

The authority of these documents - some of which are known as executive orders - is rooted in Article II of the US constitution, which states, "The executive power shall be vested in a president of the United States of America."

Why do presidents issue executive orders?

Sometimes the orders are made during wartime or to avert a domestic crisis. In February 1942, for example, President Franklin D Roosevelt signed an executive order that led to the creation of detention centres for about 120,000 Japanese Americans.

In 1952 President Harry S Truman issued an order that put the steel industry under the control of the government. He was trying to avoid a strike.

Mr Obama has made clear he has issued his most controversial executive orders because the gridlocked Congress has refused take action.

"If they're not going to do anything, we'll do what we can on our own," he told a crowd in Kansas City in July. "And we've taken more than 40 actions aimed at helping hardworking families like yours. That's when we act - when your Congress won't."

How frequently are executive orders issued?

Some presidents have relied on them extensively. Mr Roosevelt issued 3,522 orders. Others have been more sparing. President George W Bush issued 291.

Mr Obama has issued 183, putting him on pace to issue fewer per year than any president since Grover Cleveland in 1885-89.

Why are executive orders politically sensitive?

Republicans in the House, led by Speaker John Boehner, at microphone, have blocked virtually all of Obama's legislative agenda, leading him to take executive action on his own

Known as "soft law", according to Mr Shapiro, the orders do not require congressional approval. Some members of congress say they are used as a way to circumvent their authority.

Others say presidents rely on executive orders when members of Congress act too slowly or when the president feels he needs to flesh out details of a law that has been passed.

A New Yorker magazine columnist, Andy Borowitz, wrote that Mr Obama had decided to "sign a passive-aggressive executive order".

In Mr Borowitz's satirical account, the president tells members of congress: "It's OK, I don't mind doing everything myself."

Reporting by the BBC's Tara McKelvey in Washington