1. Immigrants take jobs from American workers.  Although immigrants account for 12.5 percent of the U.S. population, they make up about 15 percent of the workforce. They are overrepresented among workers largely because the rest of our population is aging: Immigrants and their children have accounted for 58 percent of U.S. population growth since 1980. This probably won't change anytime soon. Low U.S. fertility rates and the upcoming retirement of the baby boomers mean that immigration is likely to be the only source of growth in what we call the "prime age" workforce -- workers ages 25 to 55 -- in the decades ahead. As record numbers of retirees begin drawing Social Security checks, younger immigrant workers will be paying taxes, somewhat easing the financial pressures on the system.  Moreover, immigrants tend to be concentrated in high- and low-skilled occupations that complement -- rather than compete with -- jobs held by native workers. And the foreign-born workers who fill lower-paying jobs are typically first-hired/first-fired employees, allowing employers to expand and contract their workforces rapidly. As a result, immigrants experience higher employment than natives during booms -- but they suffer higher job losses during downturns, including the current one.  It's true that an influx of new workers pushes wages down, but immigration also stimulates growth by creating new consumers, entrepreneurs and investors. As a result of this growth, economists estimate that wages for the vast majority of American workers are slightly higher than they would be without immigration. U.S. workers without a high school degree experience wage declines as a result of competition from immigrants, but these losses are modest, at just over 1 percent. Economists also estimate that for each job an immigrant fills, an additional job is created.  2. Immigration is at an all-time high, and most new immigrants came illegally.  The historic high came more than a century ago, in 1890, when immigrants made up 14.8 percent of our population. Today, about two-thirds of immigrants are here legally, either as naturalized citizens or as lawful permanent residents, more commonly known as "green card" holders. And of the approximately 10.8 million immigrants who are in the country illegally, about 40 percent arrived legally but overstayed their visas.  It's worth noting that although the unauthorized immigrant population includes more people from Mexico than from any other country, Mexicans are also the largest group of lawful immigrants. As for the flow of illegal immigrants, apprehensions along the U.S.-Mexico border have declined by more than 50 percent over the past four years, while increases in the size of the illegal population, which had been growing by about 500,000 a year for more than a decade, have stopped. This decline is largely due to the recession, but stepped-up border enforcement is playing a part.  3. Today's immigrants are not integrating into American life like past waves did.  The integration of immigrants remains a hallmark of America's vitality as a society and a source of admiration abroad, as it has been throughout our history. Although some people complain that today's immigrants are not integrating into U.S. society as quickly as previous newcomers did, the same charge was leveled at virtually every past wave of immigrants, including the large numbers of Germans, Irish and Italians who arrived in the 19th and early 20th centuries.  Today, as before, immigrant integration takes a generation or two. Learning English is one key driver of this process; the education and upward mobility of immigrants' children is the other. On the first count, today's immigrants consistently seek English instruction in such large numbers that adult-education programs cannot meet the demand, especially in places such as California. On the second count, the No Child Left Behind Act has played a critical role in helping educate immigrant children because it holds schools newly accountable for teaching them English.  However, the unauthorized status of millions of foreign-born immigrants can slow integration in crucial ways. For example, illegal immigrants are ineligible for in-state tuition at most public colleges and universities, putting higher education effectively out of their reach. And laws prohibiting unauthorized immigrants from getting driver's licenses or various professional credentials can leave them stuck in jobs with a high density of other immigrants and unable to advance.  4. Cracking down on illegal border crossings will make us safer.  The job of protecting the nation's borders is immense, encompassing nearly 7,500 miles of land borders, 12,380 miles of coastline and a vast network of sea ports, international airports, ports of entry along the Mexican and Canadian borders and visa-issuing consulates abroad.  Since Sept. 11, 2001, we have dramatically strengthened our borders through the use of biometrics at ports of entry, secure cargo-shipment systems, intelligence gathering, integrated databases and increased international cooperation. The Border Patrol has nearly doubled in size in the past five years, to more than 20,000 agents. The Department of Homeland Security says it is on schedule to meet congressional mandates for southwestern border enforcement, including fence-building. And cooperation with the Mexican government has improved significantly.  Still, our southwest border is more a classic law enforcement challenge than a front line in the war on terrorism. Antiterrorism measures rely heavily on intelligence gathering and clandestine efforts that are unrelated to border enforcement.  The seasoned enforcement officials I have spoken with all contend that if we provided enough visas to meet the economy's demand for workers, border agents would be freed to focus on protecting the nation from truly dangerous individuals and activities, such as drug-trafficking, smuggling and cartel violence.  5. Immigration reform cannot happen in an election year.  The politics of immigration can be explosive and can chase lawmakers away, especially as elections near, with the result that Congress infrequently and reluctantly updates immigration laws. However, all the significant immigration bills enacted in recent decades were passed in election years, often at the last minute and after fractious debates.  This list dates back to the Refugee Act of 1980, which established our system for humanitarian protection and refugee and asylum admissions. Next came the Immigration Reform and Control Act of 1986, which made it illegal to hire unauthorized immigrants and provided amnesty for 2.7 million illegal immigrants. The Immigration Act of 1990 increased the number of visas allotted to highly skilled workers. And the 1996 Illegal Immigration Reform and Immigrant Responsibility Act charged immigration agencies with implementing significant new law enforcement mandates.  Legislative attempts to make urgently needed changes fizzled in the House in 2005 and in the Senate in 2006 and 2007, and the to-do list for this Congress is substantial. But ruling out immigration reform, whether because Congress has other priorities or because it's an election year, would be a mistake. The outline for immigration legislation that Sen. Charles Schumer (N.Y.) and his Democratic colleagues unveiled last week, together with the uproar over the Arizona law, may help convince lawmakers that there's no time like the present.  Doris Meissner, a senior fellow at the Migration Policy Institute, served as commissioner of the U.S. Immigration and Naturalization Service from 1993 to 2000. She will be online Monday, May 3, at 11 a.m. ET to chat. Submit your questions and comments before or during the discussion.  Want to challenge everything you think you know? Visit the "Five Myths" archive.
Despite the fact that we are a nation of immigrants -- or perhaps because of it -- immigration continues to be one of America's most contentious topics. The new law in Arizona authorizing police to arrest individuals who cannot show documents proving that they are in the country legally has set o...