Of all the arguments made in the long and contentious debate over immigration reform, the one heard most often, from all sides, is that our immigration system is "broken." President Obama, John Boehner, Harry Reid, Mitch McConnell, Marco Rubio, Chuck Schumer, John McCain, Dick Durbin — just about every politician who has ever weighed in on the issue has said it.

The only problem is, our immigration system is not broken. The part of the system that lets people into the United States is working — not without flaws, of course, but successfully managing the country's immigration needs every day. And while the part that keeps people out of the country, or expels them if they overstay their permission to be here, is not working very well, it's not because the system is broken, but because Congress and the president do not want it to work.

First, the part that lets people in. The United States grants legal permanent resident status — better known as a green card — to about one million people each year. The actual numbers, according to the Department of Homeland Security 2012 Yearbook of Immigration Statistics — the most recent full set of data available — were 1,031,631 in 2012; 1,062,040 in 2011; 1,042,625 in 2010; and so on going back. Legal permanent resident status is what it sounds: a recipient can stay in the United States permanently, and become a citizen if he or she chooses.

"We are the most generous nation on earth to immigrants, allowing over one million people a year to come here legally," wrote Sen. Rubio in 2013. The new million each year come from all around the world, with heavy concentrations in a few places. According to the Yearbook, in 2012, 416,488 came from Asia, while 389,526 came from Mexico, the Caribbean and Central America. That's a lot of the million right there; other sources include 103,685 from Africa and 86,956 from Europe.

Of the total, the vast majority — 680,799 in 2012 — were given green cards because they have family members in the United States. A much smaller group, 143,998, were admitted for employment reasons. The rest were given refugee status, or asylum, or came from the so-called "diversity" lottery.

Under current law — that is, if there is no immigration reform at all — those grants of legal permanent resident status will continue, million after million, year after year, for the foreseeable future. Under the Gang of Eight comprehensive immigration reform bill passed by the Senate last year, the one million each year would increase dramatically, perhaps even doubling to about two million. That's one of the key debates, if not the key debate, about immigration reform: Is it wise to greatly increase the already large number of immigrants admitted to the country each year, especially in a time of high unemployment and economic anxiety?

Of course the U.S. admits many more people from foreign countries each year under different terms. In 2012, the U.S. gave out about 527,000 student and exchange visas. (These numbers come from the State Department and are a little less precise than those from DHS.) In the same year, there were about 690,000 visas granted to temporary workers and their families, a number which included about 135,000 of the much-discussed H-1B visas awarded to skilled workers.

Again, those numbers would increase dramatically under the Gang of Eight reform bill. But the current figures in no way suggest that the system is broken. In fact, they show that it is working, perhaps more effectively than those who favor limiting immigration would like.

Now, the parts of the system that keep people out. Those parts don't work as well, but not necessarily because anything is broken.

The most egregious failure is what is known as the visa entry-exit system. Experts estimate that close to 40 percent of the immigrants currently in the U.S. illegally originally came here legally — and then remained beyond their permission to stay. In the last two decades, Congress has passed several laws that included provisions to stop so-called visa overstays; among them are the Illegal Immigration Reform and Immigrant Responsibility Act of 1996; the Immigration and Naturalization Service Data Management Improvement Act of 2000; the USA PATRIOT Act of 2001; the Enhanced Border Security and Visa Entry Reform Act of 2002; and the Intelligence Reform and Terrorism Prevention Act of 2004.

But virtually nothing has been done in all those years, through both Democratic and Republican administrations and Congresses, which suggests that the U.S. does not stop visa overstays because its political leaders do not want to. The Gang of Eight bill includes a new entry-exit system, which would allegedly crack down on visa overstays. Given recent history, however, there is absolutely no reason to believe that would actually happen were the bill to become law. There's also no reason to say the system is broken if the political leadership of the U.S. government is actively preventing it from working.

Then there is border security and interior enforcement. The 2012 DHS Yearbook includes a figure called "Aliens Apprehended," which counts illegal immigrants caught at the border and in the states. The number has been going down through the Obama administration —from 869,828 in 2009 to 752,307 in 2010 to 641,601 in 2011 to 643,474 in 2012. (The 2012 figure is lower than any year since 1973.) Some of the decrease is due to the fact that a weak U.S. economy attracts fewer illegal immigrants. But much of it is because the Obama administration has made a deliberate decision to downgrade interior enforcement.

As for deportations, the illegal immigrants sent home by the U.S. each year fall into two broad categories: those who are "removed" from the country and those who are "returned" to their home countries. There's a difference. Removal is the more serious of the two; an illegal immigrant is deemed removed from the U.S. based on an order by a judge or immigration authorities and will face criminal penalties if he tries to come back. An illegal immigrant who is returned is sent back to his home country but would not face criminal penalties if he tries to return to the U.S. illegally and is eligible to come to the U.S. legally in the future.

The number of removals has gone up each year pretty steadily for the last 20 years, including during the Obama administration. The most recent numbers were 383,031 removals in 2010; 388,409 in 2011; and 419,384 in 2012. But the number of returns has fallen dramatically under Obama: 474,275 in 2010 to 322,164 in 2011 to 229,968 in 2012. If you add removals and returns together, total deportations have fallen significantly under Obama: 857,306 in 2010 to 710,573 in 2011 to 649,352 in 2012.

Does that mean the system is broken? No — it means the Obama administration has made a policy decision to expel fewer people who entered the country illegally.

There are a number of changes that nearly everyone agrees should be made in the immigration system. The most obvious concerns the green cards handed out each year. Most people involved in the immigration reform debate — for and against — would like to see the balance between family-related green cards and skills-related green cards changed. That is, out of the one million green cards granted each year, many U.S. policymakers would prefer giving more to skilled workers and fewer to family members of people already here. A change like that could be done by specific, targeted legislation that would probably pass both houses of Congress easily, if lawmakers were not so at odds over a larger reform bill.

Most importantly, a change like that would represent a decision to adjust the nation's immigration priorities within a system that is already working, without implementing a grand, far-reaching plan to remake the system under the guise of fixing it.

So if the system basically works — and in some instances, does not work only because American political leaders don't want it to — then why do we hear so often that the system is broken? Because supporters of comprehensive reform believe that is the best way to convince the public that action is urgently needed. Listening to some of the most zealous reformers, an average voter might never know that the U.S. successfully admits so many immigrants, temporarily and permanently, each year.

The immigration reform debate touches on a lot of different subjects. But the heart of the argument is this: Supporters of measures like the Gang of Eight bill want to admit a lot more immigrants into the United States than are admitted under current law. Opponents believe the U.S. admits enough already, especially given today's straitened economic conditions.

The public is certainly with the opponents. In June, Gallup asked a sample of 1,027 Americans this question: "In your view, should immigration be kept at its present level, increased, or decreased?" Forty-one percent said they want to see immigration decreased, while 33 percent wanted it kept at its present level — making a majority of 74 percent who do not want higher levels of immigration. Just 22 percent said they wanted to see immigration increased. Broken down by party, 69 percent of Democrats wanted to see immigration kept the same or decreased, while 73 percent of independents and 84 percent of Republicans felt the same.

Those are overwhelming, compelling majorities opposing the very increases in immigration levels in the Gang of Eight and similar proposals.

But the public's opinion matters only so much. There are still important, and in some cases vastly wealthy, interest groups that want to greatly increase the number of immigrants admitted to the United States. Some genuinely want to bring in more immigrants than the millions currently allowed because they believe it would be good for the country. But for others, a desire for more immigrants just happens to coincide with an advantage to themselves that such an increase would bring: more low-wage workers, or more potential voters or more potential union members.

Given the money and political influence behind one side, and the public opinion behind the other, the debate is not likely to end anytime soon. But in the future the president and lawmakers should at least be honest enough to stop calling the immigration system broken, when in fact they just want to expand a system that is already working.