Washington (CNN) It may be the great irony of President Donald Trump's passion for tightening up immigration enforcement that his strident positions have made achieving any compromise nearly impossible, effectively dooming chances of actually getting legislation to enhance immigration enforcement in the near term.

Immigration policy trackers give astronomical odds to the likelihood of any substantive bill moving this year, especially any kind of reform. While an opportunity will come this spring in the form of money for Trump's border security package, the fight over a must-pass piece of Trump's agenda will get messy.

In House Speaker Paul Ryan's "Better Way" agenda, the only mention of immigration is border security, which has long been an objective of lawmakers and was a key focus of Trump's campaign.

"I think it's going to be really limited in scope," a House leadership aide said of what immigration-related policy could come out of Congress this year.

Despite what may be a $21 billion price tag, the hope is that enough red state Democrats up for re-election in 2018 and moderates will feel unable to vote against a package on border security.

But the obstacles that drove lawmakers to a grand bargain in 2013 haven't gone away.

That 2013 experience, when Senate overwhelmingly passed the bipartisan Gang of Eight immigration reform package to watch it die in the House, left a sour taste in the mouths of lawmakers on the idea of comprehensive immigration reform overall.

The bill was a behemoth, a collection of compromises and deals that included key elements like a solution for the agriculture industry that relies heavily on low-skilled labor, a pathway for undocumented immigrants to come out of the shadows, beefed up border enforcement and a Congressional Budget Office score that projected decreasing the federal deficit -- a rare feat for any bill -- by $200 million in the first 10 years and $700 billion in the next 10.

The first opportunity will come in the spring, when federal funding runs out and the appropriations process begins. Lawmakers expect to consider some sort of defense and border supplemental spending package to pay for Trump's promised wall, long authorized by legislation but never paid for.

Piecemeal vs. comprehensive

The No. 2 Senate Republican, Texas Sen. John Cornyn, has repeatedly said the way to move legislation is in small pieces, rather than broad strokes.

"My conclusion is we're not going to be able to do a big comprehensive bill," Cornyn told Bloomberg in November, a statement his office pointed to when asked about the state of affairs. "We've tried that. It just doesn't work. We need to secure the border and we need to enforce the law in regards to people with criminal records who are illegally in this country. And then we can have a further conversation."

Despite Republicans' insistence that a piecemeal approach through smaller bills is the key, veterans remain skeptical.

The top negotiator for Florida Sen. Marco Rubio, who was one of the GOP senators on gang of eight and who has paid a dear political price with the base since, said that Rubio originally tried to get a deal on individual pieces of legislation, so the big picture wouldn't get watered-down with deals.

"We couldn't get the rest of the gang to agree to a piecemeal approach," said Enrique Gonzalez, who now serves as an immigration attorney in Miami.

Even if all 52 Republicans in the Senate could agree on a plan, they'd still need eight Democratic colleagues to pass any bill, and Democrats are going to want something in return.

A Senate Democratic leadership aide said the party will not get on board with a bill that doesn't offer a pathway to citizenship for undocumented immigrants living peacefully in the US, for fear that if Republicans get their enforcement wish list, they'll never come back to addressing the people already here.

"If Democrats give in on doing enforcement only, they will never get the support necessary to do a pathway to citizenship," the aide said.

"If you look at the coalition that existed for the Gang of Eight bill, it was not because each member of the coalition vouched for the entirety of the bill, it's because each had priorities in the package and they realized the only way they could get immigration reform done is by supporting the whole thing."

When a bill is perceived as the one opportunity in sight to get something done, members are going to want their pet issues included, which creates headaches for leadership as they try to piece together a coalition to get 60 votes in the Senate. And any overreach by the administration and Republicans could give Democrats in tough positions a talking point to cover them voting against the package.

Add to that a legislative calendar filled with a fight on Obamacare, Cabinet nominees, a Supreme Court nominee and tax reform, and even small areas of compromise have a tough time advancing.

Democrats also have little incentive to agree to anything that might be seen by their base as working with Trump.

"You can't move something that is less controversial, because there is nothing that's immigration that's not controversial right now," Gonzalez said.

How do you pay for it?

Trump has loudly and frequently pledged to build a southern border wall, and in his first week issued an executive order ordering the construction of the wall, an increase in border patrol, hiring more immigration officers and efforts to boost resources for detention centers and immigration judges to handle more immigration enforcement.

What he hasn't declared is the price tag.

Senate Majority Leader Mitch McConnell said last month he expects the wall alone to cost $12 billion to $15 billion, though neither congressional leadership nor the White House has settled on how to pay for it. Republicans are considering a border adjustment tax as part of tax reform as one pay-for, and Trump has repeatedly declared Mexico will reimburse the US for the cost, without articulating how the US would secure such a move from an unwilling Mexico.

Democratic veterans of the Gang of Eight fight say that the deal included a pathway to citizenship largely as a pay-for. The fees collected both from applications from undocumented immigrants and from visa reform overall paid for substantial border enforcement.

"One of the best pay-fors is to get fees from undocumented individuals changing their status, if they want to pay for it, so both of those factors make it just as difficult to move forward with the piecemeal approach as the comprehensive approach," said Leon Fresco, a former aide to now-Senate Minority Leader Chuck Schumer, former Justice Department official and current immigration attorney.

Who has the capital to lead?

Another key question remains who will lead any effort on immigration policy.

All but Rubio of the eight members of the Gang of Eight bill are likely willing to work on immigration again.

Republican Sens. Jeff Flake and John McCain, both of Arizona, and Lindsey Graham, of South Carolina, have signaled they are looking for areas of consensus on immigration. Graham has introduced the bipartisan BRIDGE Act to continue to protect the young undocumented immigrants who were protected by President Barack Obama's deferred action program, and Flake and Alaska Republican Sen. Lisa Murkowski have signed on.

On the House side, a group of moderate Republicans with heavy Hispanic constituencies have long engaged in discussions on immigration reform, but without Ryan's buy-in or another prominent mainstream conservative, their work is unlikely to pick up steam.

"You would have to have political legs for immigration reform before you even talking about the Gang of Eight membership," the Democratic aide said. "That's like asking who's the eighth person to get on the Titanic."