WASHINGTON, D.C. – Texas U.S. Sen. Ted Cruz wants to place term limits on members of Congress, an idea that has long appealed to people across the political divide who have grown skeptical of the current crop of professional politicians.

But even if Cruz's amendment to the U.S. Constitution were somehow enacted by the current Congress and the states – a long-shot at best – it would not bar him from running for a third or even fourth term in the Senate.

Nor would it bar fellow Texas Republican John Cornyn from running for a fourth Senate term in 2020.

That's because terms beginning before final ratification would not count.

"The amendment, as drafted, would start the clock once it was ratified," Cruz explained in an interview. "So term limits would begin at that moment."

Cruz and Florida U.S. Rep. Francis Rooney, a Republican, introduced an amendment last week to limit U.S. senators to two six-year terms and members of the U.S. House of Representatives to three two-year terms.

Cruz offered up a similar amendment in January 2017. It went nowhere, as have a succession of term limit proposals since the 1940s, experts say. Many are intended as messaging bills to make a political statement.

For Cruz, who was elected to a second term in November, exempting current lawmakers – at least for now – represents a concession to political reality.

"My personal preference would be to make it retroactive," he said. "But as a nod to practical politics, it would be much, much more difficult to get this passed if the immediate consequence of it happening was to throw out a whole bunch of incumbents. It's awfully difficult to get them to vote for it if they'd be immediately giving up their jobs."

Cruz, who ran for president in 2016, said he would vote for a retroactive term limit proposal. But he's not willing to voluntarily term limit himself like his 2018 opponent, Beto O'Rourke, an El Paso Democrat who left the House after three terms.

"I've long said that I don't support unilateral term limits – just one person or one side unilaterally restricting themselves when the rules don't apply across the board," he said. "I think there should be a fair and uniform rule for everyone."

Nevertheless, Cruz said O'Rourke's decision to restrict himself to three terms in a relatively safe Democratic district "demonstrates the bipartisan appeal of this idea."

Still, delaying the impact on current office holders would avoid some political awkwardness in Texas, where 25 of the state's 36 House members – many of them veterans of more than a decade in Congress – are currently in their third terms or beyond.

The Texas Democratic Party, poking fun at Cruz's proposal, recently suggested that he might be calling to an "end" of his own Senate career – or that of Cornyn, whom he has endorsed for reelection in 2020.

But for Cruz, who does not face reelection until 2024, the soonest he could be term limited would be in 2036. For Cornyn, the expiration date would not arrive until 2032 – assuming the Cruz amendment were ratified before 2020.

Cornyn's office did not immediately respond Wednesday to an inquiry about his position on term limits.

Backers of Cruz's term limit proposal include Sens. Marco Rubio (R-Fla.), Mike Lee (R-Utah), and David Perdue (R-Ga.). They argue that term limits prevent career politicians from becoming captive to lobbyists and special interests in Washington.

President Donald Trump has pushed the idea as a way to "drain the swamp."

Critics say it would do the opposite by filling the halls of Congress with inexperienced lawmakers with little policy expertise, forcing them to rely even more for guidance on professional staffers, insiders, bureaucrats and lobbyists.

Casey Burgat, a governance analyst for R Street, a free market think tank in Washington, has argued that a Congress of novice lawmakers would lend itself to more corruption, not less. "Many of the corruptive, 'swampy' influences advocates contend would be curtailed by instituting term limits are, in fact, exacerbated by their implementation," he wrote in Brookings Institution paper last year.

Opponents also argue that term limits would restrict voters' choices, applying to good lawmakers as well as bad ones.

Whatever their merits, Constitutional amendments are few and far between. For an amendment to be enacted, it needs to be approved by both chambers of Congress by two-thirds, as well as three quarters of state legislatures or conventions. The 27th Amendment – the most recent – was ratified in 1992. It requires that any law changing the salaries of members of Congress not take effect until an intervening election.

Cruz, however, said conditions may be right for his latest attempt at term limits. Trump's election vindicated an anti-establishment message, and polls show support for the idea of term limits across party lines.

"When it comes to the American people, there is widespread, diverse agreement that limiting career politicians is good for America," he said. "The impediment, the one population group that has historically been resistant to term limits has been, unsurprisingly, career politicians in Washington."

He also sees the current era of divided government – with a GOP-led Senate and a Democratic-led House – as a potential plus.

"Term limits don't operate to favor or disfavor any particular political party," he said. "They don't favor or disfavor Republicans or Democrats ... Divided government may be the ideal terrain to consider and pass that constraint on everybody."

Most importantly, they wouldn't affect anyone for nearly another decade.