Should it pass, comprehensive immigration reform could have a dramatic effect on future U.S. elections. Millions of undocumented immigrants could eventually earn citizenship, which would grant them full voting rights.
Some conservative opponents of the bill say that should serve as reason-number-one to torpedo it. Talk radio host Rush Limbaugh said last month that passage of the bill would be "a death sentence for the Republicans."
"Let's say you have ten million illegals, seven million of them are automatically gonna vote Democrat," Limbaugh said. "Republican Party's finished."
It is true that Latinos and other groups with recent immigrant roots voted strongly for President Obama in 2012. And if all 11 million undocumented immigrants, from every creed and country, had voted for Obama last year, his victory would have turned into a historic landslide.
Legalizing millions of undocumented immigrants would certainly impact electoral politics, but it would be presumptuous to assume that immigration reform would spell the end of the Republican Party.
Under the plan proposed in the Senate, most legalized immigrants would not be eligible to vote until 14 years from today, at the earliest. It's not clear how many undocumented immigrants will eventually seek full citizenship and become voters. And it's tough to predict what the political preferences of these immigrants will be over a decade from now.
If an undocumented immigrant begins on the path to citizenship starting next year, the soonest he or she would become eligible to vote is 2027. The first presidential election they would be able to participate in is the 2028 contest.
"It's unlikely that these folks would be able to vote in 2016 or 2020," said Mark Hugo Lopez, associate director of the Pew Hispanic Center. "It would be much later."
One major exception to that would be young undocumented immigrants brought to the U.S. as children, known as DREAMers. They would receive a faster path to citizenship. They could vote as early as 2019, making them eligible to participate in the 2020 elections.
Still, immigrants currently in the U.S. without documentation would not be able to go to the ballot box for at least seven years. Even then, it isn't likely that all 11 million would seek full citizenship and become voters.
Under the 1986 amnesty law -- the last time the U.S. created a path to citizenship for undocumented immigrants -- only about 40 percent of the 2.7 million legalized immigrants had become citizens by 2009 (less than 1.1 million), according to the Pew Hispanic Center.
It's impossible to tell if the naturalization rate would be smaller or larger under the current bill because there are too many variables to get an accurate estimate, Lopez said. For example, we don't know how many people would be able to pass a criminal background check or the number of previously deported immigrants who would be able to return and seek provisional status. But with all the conditions required for citizenship and the 13-year wait, it's safe to assume that a large number will not become full citizens.
It's also important to note that not all citizens vote. Only 58 percent of the voting-eligible population cast a ballot in the last presidential election, according to the United States Elections Project.
And when it comes to determining if legalized immigrants will vote overwhelmingly Democratic, that also remains to be seen. An overwhelming 71 percent Latino voters backed Obama in 2012, according to exit polls. Asian-American voters supported him in virtually the same numbers. That suggests an influx of millions of Democrats onto the voter rolls by 2028.
The best (albeit flawed) estimates show that Latinos eligible for legalization also favor Democrats, but not at the same rate as Latinos who voted in the past presidential election.
Fifty-four percent of Latinos without U.S. citizenship or a green card said they identify with the Democratic Party, according to an October 2012 Pew survey, while 19 percent identified with the Republican Party. But a large swath (28 percent) said they either don't have a preference or don't know.
That means that the GOP has about a decade to work on fixing its broken image among Latino voters if it wants to make inroads with a potentially large number of undecided, legalized voters. That makes the stakes of the current immigration debate even higher.
"I think it depends on the dynamics of future elections, who are the candidates and what the issue will be," Lopez said.
Introducing a large group of newly-naturalized voters into the population at once will undoubtedly change the American electorate. For example, by 2020, 7.1 percent of the electorate in the GOP-stronghold of Texas would be previously undocumented, according to an estimate by Business Insider.
But it's important to remember that the main driver of growth in the Latino vote now comes from Latinos born in the U.S., and not immigrants. That means any successful strategy for Latino outreach must account for immigrants and non-immigrants alike.