His leadership committee, Reinventing A New Direction PAC, has also been able to attract small-dollar donors. During the previous two years, it raised more than twice in small-dollar contributions what it did during the 2011-2012 election cycle, while increasing its itemized contributions total by 14 percent.

Rand Paul’s announcement timing and the F.E.C.’s reporting schedule mean that we won’t get a good idea whether Ron Paul’s donors are early supporters of Rand Paul’s candidacy until July 15. There are some small glimpses, however: RandPaul.com is displaying names and cities of donors, and among those shown on Tuesday was Adil Khan of Des Moines, who was a volunteer on Ron Paul’s campaign.

Even so, the lineage of most small-dollar donors will be known only to the campaign. At that point, it will be content to call them “Rand Paul donors,” regardless of whether they supported Ron Paul in the past.