Nevada voters are heading to the polls Tuesday, but this week’s primary elections will be little more than a formality on the way to two general election battles that will determine just how much the Silver State has changed politically in recent years.

When former state Senate Minority Leader Dina Titus (D) entered the 3rd district race in early May to challenge Rep. Jon Porter (R), the contest in the suburbs of Las Vegas shot to the top of the list of seats that party leaders are hoping to change from Republican to Democratic hands this fall.

And not too much further down that list is the 2nd district race where former Nevada Democratic Party Chairwoman Jill Derby (D) is in a rematch with freshman Rep. Dean Heller (R) after losing last cycle by 5 points.

Less than 100 days out from the general election, independent analysts like Las Vegas-based political columnist Jon Ralston agree that the Porter-Titus race presents a better opportunity for Democrats.

“The guy with the real problem is Jon Porter,” Ralston said.

A late July Las Vegas Review-Journal poll found Titus ahead of Porter, 43 percent to 39 percent, with 7 percent undecided.

As the 2nd and 3rd district races have heated up this year, Democrats have made much of their voter registration surge, which has turned a deficit of a few thousand registered voters two years ago into a lead of nearly 61,000 enrolled voters statewide as of last week. That translates into a 25,000-voter advantage for Democrats in Porter’s 3rd district. In the 2nd district, which has long been the GOP’s stronghold in the state, Democrats have whittled away the Republican registration lead to 29,500 voters as of last week.

But simple registration numbers aside, Democrats are optimistic that this year’s political environment is forming a perfect storm for a blue wave to sweep across the Nevada sands.

First, Democrats feel the presidential race in this battleground state provides a much better trickle-down effect for Titus and Derby than it does for Porter and Heller.

Whereas presumptive Republican nominee Sen. John McCain (Ariz.) came in third during the presidential caucuses earlier this year, presumptive Democratic nominee Sen. Barack Obama (Ill.) actually won more delegates in Nevada than Sen. Hillary Rodham Clinton (N.Y.) did. And though the Republican who actually won Nevada, Massachusetts Gov. Mitt Romney (R) is still in the mix as a possible vice presidential pick, Clinton is already hard at work in Nevada. She appeared Friday at an Obama rally at one of 13 offices throughout Las Vegas (nine of which fall in the 2nd or 3rd districts) that Obama has opened or has plans to open.

Democrats also appear to have an advantage when it comes to other high-profile state figures. Porter and Heller certainly won’t want to associate themselves with scandal-plagued Gov. Jim Gibbons (R), whose statewide approval ratings were so low in June that McCain passed him over to serve as his Nevada campaign chairman and picked Lt. Gov. Brian Krolicki (R).

Republicans do have Sen. John Ensign (Nev.) in their corner, and while the Senator has helped Heller and Porter with thousands of dollars in PAC donations and plans to help with fundraising events, his focus on Nevada will be limited this fall. As National Republican Senatorial Committee chairman, Ensign has his hands full defending 23 seats this cycle compared with 12 for the Democrats.

Meanwhile, Democrats have in their corner Senate Majority Leader Harry Reid (Nev.), a man who who is credited with rebuilding the Democratic Party in Nevada and putting it in a position to be competitive this year. Along with his interests in this fall’s Congressional races from a party-building perspective, Reid also has a vested personal interest in defeating Porter as the three-term Congressman has repeatedly been mentioned as a potential challenger to Reid in 2010.

Another well-known state official who will be working hard for Titus and Derby this fall is Rep. Shelley Berkley (D), the only Member from the state who is not facing a competitive general election this fall.

“Both Jill Derby and Dina Titus were bridesmaids at my wedding. We’re very close, and we know each other very well ,and we’ve been strong political allies for well over 20 years,” Berkley said Friday.

Berkley has already hosted events for both Titus and Derby in Washington, D.C., and Nevada, with several coinciding with Clinton’s visit to the state last week.

And then there’s the support Titus and Derby have received from the national party. Both women have been added to the Democratic Congressional Campaign Committee’s “Red to Blue” program (Derby was a much more recent addition), and the committee has reserved more than $900,000 in air time in the 3rd district alone.

Meanwhile the pro-abortion-rights group EMILY’s list has also gotten behind both Titus and Derby (again, Derby was a more recent addition), and both women, who have already shown impressive fundraising totals on their own, should now further benefit from the group’s massive fundraising base.

But for all the factors that appear to be aligning for Titus and Derby this cycle, Republicans say that they simply have the better candidates and that Democrats are trying to “prop up” their “flawed” candidates.

“The Republican candidates in the 2nd and 3rd have both been great candidates, are running very competitive campaigns, and we believe they have the advantage,” National Republican Congressional Committee spokeswoman Julie Shutley said. “They are both running races based on their independent records and their work on behalf the people of Nevada.”

Shutley called Derby a “rerun” against a Congressman who now enjoys the advantages of incumbency after winning an open seat last cycle in one of the worst environments for Republicans in decades.

Porter, meanwhile, has shown a continued ability to win his battleground district, beating out a former Reid staffer in the previous cycle by less than 4,000 votes. Titus, on the other hand, is coming off a losing gubernatorial race in 2006 — although Democrats are quick to point out that Titus edged out Gibbons in the 3rd district in that contest.

Ralston said that when Porter helped draw the 3rd district as a state legislator, all the growth was supposed to be Republican.

“Now there’s 25,000-plus more Democrats than Republicans,” Ralston said. “With all the partisan voting patterns that occur in presidential years, with Democrats really focused on that race, with Harry Reid seeing Jon Porter as a potential 2010 opponent and wanting to get him off the map now, Porter has a real rough ride here.”