It's D-Day for Ron Paul's 2012 Insurgency

Today will mark the end, or the ultimate success, of Ron Paul's delegate insurgency.

After a primary campaign in which Paul's team focused on the most ignored parts of the GOP process, winning delegates in overlooked caucus states and organizing around delegate votes at state conventions, Paul supporters will have their last chance today to ensure an official presence for Paul at the Republican National Convention in Tampa, Fla.

The Nebraska GOP convention - the last in which delegates will be up for grabs - will offer a long shot at putting Paul over a critical threshold.

Paul is on the cusp of winning enough support to secure a 15-minute speaking slot and to have his name placed on the ballot of official candidates for the nomination at the Republican National Convention in August.

Mainstream Republicans would blanch at such a prospect, given that Paul's views on the Federal Reserve, currency, foreign policy and America's global military presence run antithetical to Republican orthodoxy. Republican Nebraska Gov. Dave Heineman, a supporter of Mitt Romney, has been making phone calls and organizing delegate support for Romney to block Paul's supporters at the state convention.

If Paul can demonstrate the support of a plurality of delegates from five states, Republican National Committee bylaws require he be allowed to speak in Tampa. Paul has enough delegates from Iowa, Minnesota and Maine, and Louisiana's still-disputed delegation could put him over the five-state mark, if his supporters prevail in Nebraska.

Paul backers will face long odds in Nebraska, where the convention's voting attendees were selected in early June at county conventions. Attendees of those events had to register by March 1, meaning that Saturday's outcome reflects a months-long organizing push by libertarian supporters of Paul.

"We have a rough count" of state-convention delegates and whom they support, said Laura Ebke, who leads the Nebraska chapter of the Republican Liberty Caucus and who is the chief organizer of Ron Paul supporters in the state. "We don't have a majority. We have a significant minority."

Saturday's results will depend on who shows up. The convention provides for 400 voting delegates, but state party Executive Director Jordan McGrain said he does not expect all to attend. More than two thirds will likely show up, he said.

Paul, who has stopped campaigning in new states, is not personally organizing around the Nebraska convention, Ebke said. According to Ebke and McGrain, neither Paul nor Romney have staff in the state working on this event.

The Republican candidate and libertarian hero will have a presence in Tampa, Fla., regardless of what happens in Nebraska. His campaign is planning a rally, and supporters have planned a festival, to coincide with Tampa's preparations for the Republican National Convention.

But unless Paul meets the RNC requirements as a candidate for the nomination, he has no guarantee of an official presence inside the Tampa Bay Times Forum. He'll be at the mercy of convention organizers and presumptive nominee Mitt Romney to grant him speaking time, entrance to the event and visibility as a participant.

In 2008, Paul was shut out of the Republican convention in Minnesota. As delegates rallied around the ticket of John McCain and Sarah Palin in the Staples Center, Ron Paul held his own event across town.

Paul's status has risen since then, as he outdid his 2008 vote totals in key states along the way in 2012, but his views still make him a pariah to some. It's been suggested, most prominently in a column by Republican tax maven Grover Norquist, that Romney would be wise to seek a reconciliation with Paul in an attempt to bring his supporters into the fold.

Paul's campaign expects to bring as many as 500 supportive delegates to Tampa, out of 2,286 total, meaning his floor presence could be noticeable with or without the assent of Romney and the convention's organizers. But unless his backers can overcome long odds in Nebraska, Paul is guaranteed nothing from those putting on the event.

UPDATE: Paul's supporters have fallen short in Nebraska, winning two of the state's 35 national-convention delegates, Ebke confirmed to ABC News.